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Old 16th Feb 2019, 11:38 am   #81
1100 man
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Default Re: 1938 Murphy A56V television restoration

Hi Catkins,
Great restoration- many thanks for writing it up in such detail. It's always good to see such attention to detail. At least when everything is that rusty, the decision to restore a component or leave it alone is made much easier!

I've just been reading your detailed description of your re- plating methods. We bought several similar kits to plate small car components. We try, when doing a restoration, to send a batch of stuff to the platers in one go but there are often small items that get missed, so being able to plate them ourselves would be great.

So far, our results have been pretty poor: due, no doubt, to bad practice on our part.

Referring to the pot backs shown in post 74, firstly, how was the very rusty back cleaned up? We would have sand blasted it with very fine sand, but whatever method was used, it would have been very pitted. The re-plated item looks perfect- did you not have to go through the copper plating process outlined in your earlier post?

Some of your pictures show a very shiny finish- was that as it came out or have you polished those after plating?

Many thanks
All the best
Nick
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Old 17th Feb 2019, 4:31 am   #82
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Default Re: 1938 Murphy A56V television restoration

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Originally Posted by 1100 man View Post
Hi Catkins,
Referring to the pot backs shown in post 74, firstly, how was the very rusty back cleaned up? We would have sand blasted it with very fine sand, but whatever method was used, it would have been very pitted. The re-plated item looks perfect- did you not have to go through the copper plating process outlined in your earlier post?
No, it was a single plate, as I said in my previous post.

As I said in my previous post, it is really a question of try and try again. If the plate doesn't look the way you want it to, put it into the acid pickle, burn off the previous plate, fix whatever the problem was, and do it again, perhaps experimenting with different approaches.

The pot backs were an interesting problem. The problem is that they have writing stamped into them (the ohmage as shown in the previous photo). Repeatedly plating with copper will "fill in" the writing leaving it indistinct (and certainly not keeping the crisp appearance).

The reason for that should be obvious, you're using repeated plating and polishing to smooth over imperfections, and the process doesn't distinguish between pitting and writing, it's all the same to it.

So the question was I want to do this with one plate, *and* I want to get a good finish too.

So the finish before plating had to be good, which required a lot of slow hand sanding, going down the grades to fine polishing paper. After a couple of test platings, and more sanding/polishing of the metal before plating, I finally got a finish I found acceptable. After plating, I then polished the result to produce the final finish. This is because for very fine polishing, it is easier to polish the zinc plating, than the steel, as it is softer. But obviously, because the plate is fairly thin, it will only stand a small amount of polishing, otherwise you polish through the plate.

In otherwords most of the polishing had to be on the steel, as I only wanted one plate. But I allowed a small amount of polishing on the zinc plate to perfect it where it was easier to do so.

Quote:
Originally Posted by 1100 man View Post
Some of your pictures show a very shiny finish- was that as it came out or have you polished those after plating?
As mentioned above, for the pot backs, I polished them up to a final appearance after plating, for the previous reasons.

For the other finishes, repeated plating and polishing was done to produce a mirror surface *before* the final plate. So the finishes are the final plate, without any extra polishing.

In otherwords if you polish after plating, that then becomes the input for the next plate. You stop when you have a finish *after* plating that doesn't need polishing.
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Old 17th Feb 2019, 9:46 am   #83
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Default Re: 1938 Murphy A56V television restoration

Quote:
Originally Posted by 1100 man View Post
We would have sand blasted it with very fine sand,
Electrolytic de-rusting with washing soda is better. Here's one example of how to do it:
Electrolytic-Rust-Removal-aka-Magic/
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Old 11th Mar 2019, 9:27 am   #84
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Default Re: 1938 Murphy A56V television restoration

Apologies for the two week delay in updates, I have been very busy in work, and this has left no time for anything else. As it is, it is now very late, and so I'm going to have to be very quick in this posting.

The last posting left me explaining all the things planned for my 2 week vacation over Christmas 2016 (and yes there's still almost two extra years of work still to detail).

As planned, I got the respraying of the top of the chassis done over late November and early December, leaving the paint work hard enough to start work on the underneath of of the chassis.

I had already had a good look at the paintwork underneath the chassis and decided it didn't need respraying, this was a very good bonus as it meant I didn't have to strip off all the components/tag-boards on the underside just for respraying, and it left them in place for the careful task of rewiring and component replacement (of the various restuffed waxies, electrolytics, and other repaired or replaced components).

There is a good reason why I wanted to keep the underside electronics in as undisturbed and original condition as possible. I didn't want to introduce issues/instability in the circuits. Pre-war televisions are notorious for pushing the available electronics to the limits due to the then high frequencies employed, and this often involved careful placement of components, wire routing and wire lengths. If you ever see something "unusual" in the placement or routing, this is usually the reason why, and you'd be stupid to loose this in any disassembly/reassembly and rewiring.

Photo 1 shows an obvious example of this, the frequency changer circuit. The entire frequency changer circuit is built on-top of the oscillator coil, and the whole assembly is immediately over the frequency changer valve socket. This makes an extremely dense and difficult to work with circuit, but, the obvious intent is to make the signal paths (wire-length etc) as short as possible. This is the reassembled and replaced circuit and pains were taken to match it exactly against photos taken before removal and disassembly. I replaced the connecting wires even though I knew I would eventually replace them, but, it is better to get everything right when replacing, and then follow that as a guide when replacing the wires, as it is less to concentrate on at that time.

My replacement of components and rewiring was pragmatic. I generally took one circuit at a time, and replaced components and rewired in "one go" to minimise the overall level of disruption. Rewiring was done one wire at a time, point to point, keeping each new wire the same length and preserving the routing. The components were replaced exactly using photographs.

The one exception to this was inter-circuit wiring, which I preferred to do separately, either before or after individual circuit rewiring, depending on circumstance. This is obviously because they relied on a global perspective to get the rewiring right. This mostly meant the filament wiring and the various HT feeds.

The filament wiring in the set was quite interesting. There are three separate circuits, with each one obviously connected to the same pins (on the power unit socket). The first circuit powers the valves on the lower side of the chassis (framebase, sync separator, and video detector/amplifier), the second circuit runs up the side powering the video IF valves, FC valve and HF valve. The third circuit powers the valves on the top side of the chassis, which are the linebase and the audio circuit valves. Additionally each circuit is wired the opposite way for negative and positive. The negative is daisy chained from one end of the circuit to the other end, and the positive is daisy chained from the other end. This I found quite unusual, and I can only assume it is an attempt to reduce inter-circuit interference.

There are separate three HT feeds in the circuit, and I again took pains to preserve the exact wiring between circuits. There were not many surprises here, but some circuits are daisy chained, and others are fed from a central HT point.

Photo 2 is a photo of the top left hand corner of the chassis in the middle of rewiring, with the waxies replaced. This shows the HF, Audio IF and Audio detector stages.

Photo 3 shows some rewired aerial/IF coils and Photo 4 shows one of them before rewiring.

One thing which perhaps needs to be mentioned here is the replacement wire. For this set I wanted to use wire that preserved the original vintage appearance. The cotton wire in the set was very dirty and very faded, but, one thing which was clear was that it was two-tone striped, with a darker colour and a lighter colour. This seems to me to be a particularly 1930s style, as I've never seen it in post war sets (but as usual there's always a first time which disproves this).

I looked for a long time for someone selling vintage NOS striped wire, and after a couple of months I finally found someone who had come across about 10 or so unused reels of different coloured striped wire. This wire was made in the early 1950s to a vintage colour coding. This was offered by the metre and it is easily the most expensive wire I have ever bought. But, I think it was worth it to preserve the original appearance.

Photo 5 is a view of the top of the resprayed chassis, showing the replaced coils and cans. At this point the rewiring was complete (except for the controls on long looms of wire, which would come much later).

Finally it looked to me, as if this might one day be a functioning TV again, rather than a lost hope.

But I'm out of time. This is mostly a pure brain dump due to lack of time, and I don't have time to edit it. As Pascal famously said, I would have written a shorter letter, but I did not have the time.
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Last edited by Catkins; 11th Mar 2019 at 9:35 am.
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Old 11th Mar 2019, 11:42 am   #85
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Default Re: 1938 Murphy A56V television restoration

Quote:
Originally Posted by Catkins View Post

I looked for a long time for someone selling vintage NOS striped wire, and after a couple of months I finally found someone who had come across about 10 or so unused reels of different coloured striped wire. This wire was made in the early 1950s to a vintage colour coding.
That was well done.

The only vintage TV I have restored and re-wired with fabric replacement wire is the Andrea KTE-5. The wire was available new (reproduction) from Antique Electronics in the USA.

I found when I stripped the ends, using a scalpel, the fabric weave would start to un-twine. So, for about 5 mm , I painted it with clear varnish that stuck the fabric threads together. (Photo attached of under chassis of KTE-5 Television set, 1939)

After that experience, for all my restorations, both radio & TV, I went to silicone rubber covered wire. The reason is it looks exactly like vintage rubber hookup wire, but is totally heat resistant and it does not burn or retract regardless of the soldering temperature (unlike PVC). It comes from RS components.

PS: Your restoration/s set a very high standard for the forum, it is eye candy to see the the work.
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Old 8th May 2019, 7:52 am   #86
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Default Re: 1938 Murphy A56V television restoration

It was a while ago since I managed to make an update on this thread. Usual reasons apply, too much work and too little time.

I left off after starting to put the television back together after rewiring. Over the next month or so I concentrated on putting the audio section back together, with the aim I could then do an audio only test of the set. This would be a good intermediate check that hopefully everything so far was correct and functioning (power supply, wiring, HF/FC, audio IF and output stages). In fact I also put the video IF stages back together (leaving timebase/scanning/focus etc.), with the idea I could then also check video IF amplification was working. This was done by March 2017 (picture 1).

Happilly with one exception it worked first time on turn-on. That is on the first initial turn on I got a cloud of smoke emanating from the FC IF can. This proved to be an over-heating resistor caused by a HT short to one of the secondaries. As can be seen in picture 2, some of the wiring is bare, and the bare-wire HT feed was touching one of the secondary windings. Luckily this was caught in the first few seconds with the set on a variac slowly turning up the voltage, and so no damage was caused.

Once that was fixed, it perhaps "boringly" worked first time, with no days of fault tracing and fixing. This was on one hand gratifying and on the other hand a bit of an anticlimax. I spent a couple of hours in a soak test listening to 60s vidoes off ytube, checking the quality of reproduction (which was very good, the huge mains energised loudspeaker has very good reproduction). Then it was back to work.

The next thing to do was to address the CRT mounting, and check the differences between the CRM91 and the CRM92 CRTs.

Perhaps a recap (no pun intended) is needed here. The Murphy A56V was designed to use a 9 inch CRM91 CRT, but the CRM91 CRT in the set was broken, and getting replacement CRM91 CRTs is all but impossible. But, all is not lost. The slightly later 9 inch CRM92 CRT (introduced in 1939) is electrically identical to the CRM91 and can be used as a replacement. In fact FERNSEH on this forum had previously succesfully used a CRM92 CRT in his A58V.

But the CRM92 has a lower deflection angle (surprising for a later tube). and so it is differently dimensioned. The task was to work out how this affected the existing mounting arrangements.

If you look at photograph 3, you can see the mounting arrangement. The CRT is positioned vertically in the middle of the chassis in a large hole. The shoulder (where the gun joins the bulb) lies at the level of the chassis, where the scan coils are attached. The focus coil lies below the level of the chassis, within a sub-assembly bolted to the bottom of the chassis. The CRT sits in a sub-assembly mounted on top of the chassis, this consists of a flat plate with a (larger) hole where the CRT sits, and two support brackets which hold the plate above the level of the chassis.

So how does the different dimensions of the CRM92 affect the mounting? Well the CRM92 is longer due to the lower deflection angle, but the bulb widens out more rapidly than the CRM91. The result is the CRT sits higher within the hole on the mounting plate. So the extra length of the CRT is shared, the CRT sticks out higher above the mounting plate, and sticks out further below the chassis.

Can this extra height and depth be accommodated within the existing arrangements? The answer is sadly no.

The major problem is the CRT sticks out about half an inch too far even with the lowest height settings (see later). There is not enough clearance bwtween the CRT and the safety glass in "presentation mode" (where the chassis is swivelled at a 45 degree angle to place the CRT against the safety glass). There is also the problem that the shoulder is too high in respect to the scan coils, but, this is a secondary issue as in practice it will be fixed as a side-effect of fixing the height problem.

How to fix the height problem? The mounting brackets are slotted, but the maximum depth of the slots only brings the plate to the top of the mounting brackets. The plate needs to adjusted to about half an inch, or 1 inch (to give adjustment leeway) below the height of the mounting brackets.

FERNSEH solved this by basically bolting an extra set of brackets onto the plate, which sit above the plate. These brackets are then bolted to the existing mounting brackets, which allow the plate to sit about an inch below the top of the mounting brackets. You can think of these extra brackets as basically spacers. The spacers are bolted to the mounting brackets, not the plate itself.

I wanted to try something different, because I didn't like the idea of drilling holes in the existing plate to add the extra spacer brackets. If I ever got a CRM91 CRT I would never be able to put the set back to exactly how it was, because the drilled holes will still be there.

Now the basic problem is the mounting brackets are simply too high to accommodate the CRM92 tube. If the mounting brackets were lower, then the problem wouldn't exist.

So my decision was to fabricate new mounting brackets, these being otherwise identical to the originals but an inch lower.

I choose to fabricate them from fibre glass, as fibre glass has the necessary strength, but is easier to work with than metal.

Photograph 4 shows the frabricated mounting plates, with the slots cut, but before final sanding, mounting hole drilling and painting.

Photograph 3 is actually a photograph of the newly finished and painted mounting plates in place. I doubt anyone would easily differentiate them from the originals.

There are some more things which needed to be done, but, that will have to wait till next time.
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Old 10th May 2019, 3:36 am   #87
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Default Re: 1938 Murphy A56V television restoration

To continue from my previous post.

I mentioned previously that the extra length of the CRM92 CRT with the original arrangement is shared, with the bulb sticking out a bit more above the chassis, and the CRT gun sticking out a little more below the chassis.

Obviously, once you fix the extra bit sticking out above the chassis by lowering the CRT mount brackets, all the extra length of the CRT now sticks out below the chassis.

As mentioned previously, below the chassis is bolted a sub-assembly which holds the focus coil, focus coil adjustment mechanism, and the CRT clamp.

The focus coil adjustment mechanism can move the focus coil up and down the CRT neck by about an inch. With the extra length of the CRT tube that means everything fits at the lowest setting, but it obviously leaves no room for focus adjustment.

To get that back, the sub-assembly has to be spaced about half an inch below the chassis. Obviously, this can be done with long bolts, and adding some spacing nuts.

Pictures 1 and 2 show the inside of the sub-assembly with the focus coil, and the outside of the sub-assembly with the CRT clamp. Both are obviously pre-restoration. These are there to illustrate the above text.

Picture 3 shows the under-side of the chassis with the long bolts in place, which the sub-assembly will be bolted to, with spacer nuts.

Picture 4 shows the sub-assembly and focus coil housing cleaned just before respraying.

Photo 5 shows the resprayed outside of the sub-assembly with the cleaned and restored CRT clamp arrangement.
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Old 28th Sep 2019, 1:22 am   #88
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Default Re: 1938 Murphy A56V television restoration

Apologies for the gap in posting, usual reasons. Normal postings will hopefully be resumed shortly.

In the mean time, a quick posting about CRM92 CRTs. I spent quite a while looking for a good emission CRM92, and found one that was OK but on the low side, and a CRM92A with better emission but which obviously needs a higher EHT.

All were really only OK in darkness on the Murphy A56V (only 4.5Kv EHT). I think judging by other comments on here, that this is fairly typical.
.
But in the Royal Wootton Bassett BVWS auction on 7th July there appeared a restored Baird T164 with a RACS rebuilt CRM92 (a Panrock restoration). I thought the CRM92 would certainly be better than what I had.

Surprisingly, the television went for less than the cost of the RACS rebuild, with myself as the highest bidder.

I have fitted the RACS tube into the A56V, and I have to say the difference is astonishing. Much brighter, much better contrast, and it is viewable in daylight. The phosphor does have more persistence than an original CRM92, but it doesn't cause any viewing problems.

I have attached some photos. Photos 1 and 2 are of the rebuilt CRM92 in the T164, and Photos 3 and 4 are of it in the A56V displaying the testcard, in darkness and daylight respectively.
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Old 28th Sep 2019, 10:23 am   #89
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Default Re: 1938 Murphy A56V television restoration

Excellent result! And nice to see a RACS CRT in operation.

Peter
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Old 28th Sep 2019, 10:33 pm   #90
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Default Re: 1938 Murphy A56V television restoration

The original Mazda CRM91 failed very quickly after I acquired my A58V and the only available replacement tube at the time was a Mazda CRM92A. As is well known the CRM91 is one inch shorter than the post-war tube.
In order that the CRM92A would fit in the A58V adaptor plates and spacers were made. Much later on and thanks to the kind donation of a good CRM91 by another Forum member the CRM92A and those special parts were replaced by the correct tube.
When I finally sort the problems I'm having with my EMI sets I'll fire up the A58V again.

DFWB.
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Old 19th Feb 2020, 9:48 am   #91
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Default Re: 1938 Murphy A56V television restoration

Last year I found it increasingly difficult to complete this thread, due to lack of time. The company at which I worked got taken over by another company, and under new management, my workload doubled and steadily increased throughout the year to an impossible level. Things came to a head just before Christmas, and I resigned. The upshot is I now have some time to complete this thread, apologies for the length of time it has taken.

Reviewing the thread I left off at about May 2018, I'm going to fast-forward over the 4 or so months to September 2018, at which point I had put the set back together. Obviously once the set was back together, it was time to turn it on and test it. But, I was aware I had completely rewired it, and I first wanted to do some sanity tests before turning it on. So I checked the HT resistance to earth in various parts of the circuit, which should show up major mistakes. One testing issue here which I hit is there is often a legitimate low HT resistance to earth in one part of the circuit, which can mask out unexpected low resistances elsewhere. But, on this set I discovered I could isolate various parts of the circuit by unplugging the loudspeaker (with HT going through the field coil, as it is one of Murphy's huge mains energised loudspeakers), and the PSU (power supply unit).

Overall HT resistance to earth was OK, but unplugging in various combinations, showed there was an unexpectedly low resistance to earth in the timebase circuit. Checking of that circuit showed I had incorrectly connected two wires to the occasional controls (line/frame hold, height/width etc). Some of the occasional controls are in the cathode circuits, and some are in the anode circuits, and the miswire effectively connected HT to the cathode circuit of one of the line/frame output valves, which could have led to some unpleasant results if not caught early.

Once that was fixed, the HT resistance was as expected, and I could not discover any more faults. Time to turn it on (without a CRT and EHT transformer disconnected, no point in having lethal voltages present when I'm concentrating on the rest of the circuit first and may want to do some live tests). Again taking no chances, I connected up four multi-meters to monitor the HT at various points, and slowly brought up the voltage on a variac. After a couple of hours, I was at max voltage without hitting any problems, and I could hear the line whistle from the LOPT.

Time to inject a signal, with an oscilloscope connected to the video detector diode (because as yet there was no CRT). I got sound on the loudspeaker, but, disappointingly no signal on the video detector diode. Working backwards from the video IF stages (3 stages) with the oscilloscope, I discovered the fault lay with the first IF stage. Visually checking the circuit showed a short circuit on the valve base due to wires touching. Once that was fixed, I got a video signal on the video diode (Photo 1).

The next weekend, I connected up EHT and put in a low-emission CRM 92 CRT. This was obviously in case there were faults with the deflection which might damage the phosphor, no point in damaging a good tube. The result was very disappointing. Non-existent focus, which obviously made it difficult to see if there was any raster or picture, but, it did show line and frame deflection was working (at least to some extent).

Doing some voltage measurements showed there was voltage on the focus coil, but no voltage drop across it, when there should have been about 10 volts. The focus coil is bypassed by a 100 uf capacitor (in the refurbishment of 1946 this was changed to two 50 uf capacitors, which I restuffed). One of the 50 uf capacitors had exploded and was now a short-circuit (Photo 2).

At that point I could not discover why the capacitor had failed, I checked the focus circuit and time-base HT circuit and found no problems. Later I realised I'd done a stupid thing when testing the set for sound when incomplete about 6 months before (see postscript).

Discovering no underlying fault, I restuffed both capacitors (the other, though not exploded, had gone high). At this point I got a picture (Photo 3). This was at max focus. Obviously the focus coil was positioned incorrectly. But importantly, the question was did my modifications (to the mounting to accommodate the longer CRM92) allow the focus coil to be positioned to allow focus (and centring) to be obtained? It would be embarrassing if it didn't, but, happily the answer was Yes.

With a better tube, and after a couple of hours adjusting the focus coil positioning, gain, fine tuning, and the various other controls, I produced a much better picture (Photo 4). Which I thought was very good progress.

Postscript: The cause of the exploding capacitor became obvious later. I had tested sound on the set about six months before when I thought the time-base circuit was completely disconnected and inactive and so it would be harmless. But, it wasn't, there was still a circuit from the time-base HT to earth, and with the focus coil disconnected, the voltage across the capacitors would have been much higher than intended.
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Last edited by Catkins; 19th Feb 2020 at 9:57 am.
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Old 19th Feb 2020, 6:49 pm   #92
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Default Re: 1938 Murphy A56V television restoration

Hi Catkins,
I'm sorry to hear of all the trouble you've had, but glad you have come back to persevere with the story.
I could suggest you turn it into a BVWS article, but then again it is probably time that I wrote one myself.

Cheers
Andy
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Old 20th Feb 2020, 6:57 am   #93
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Default Re: 1938 Murphy A56V television restoration

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Hi Catkins,
I'm sorry to hear of all the trouble you've had, but glad you have come back to persevere with the story.
I could suggest you turn it into a BVWS article, but then again it is probably time that I wrote one myself.

Cheers
Andy
Thanks Andy. It seems to be how things are in IT at the moment, productivity is no-longer got by investment, but by sweating the assets (i.e. staff). I had a pretty dreadful time back between 2001 - 2011 following the dot com crash. Every British based company I worked for got into trouble after a year or two, and the job went through the familiar descent into impossibility. Sadly most of those companies are now retail parks or housing estates (GEC Plessey, Philips, NXP semi etc). Finally I got a job with an American company working from home (Redhat). But they slowly went the same way, which accelerated once they got bought by IBM

I have given myself a couple of months break, which I hope to catch up on a lot of things I couldn't do last year. The major thing at the moment is to get back up to speed on the restoration of my HMV 900, which pretty much stalled last year. I should hopefully be making a couple of posts on that soonish.

I did think about writing a BVWS article last year, but, it became an impossibility. At the moment it really depends on when I decide I should looking for another job .
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Old 20th Feb 2020, 8:51 pm   #94
Stylo N M
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Default Re: 1938 Murphy A56V television restoration

Hi Catkins,

There is no way i could of done what you have done, what a wonderful restoration and a great video on youtube, and write up, fantastic.

Yes i'm with you there, regarding lifes changes believe me, but i do sincerely hope that you find something suitable regarding work soon, you have my thoughts and well done

Paul
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Old 21st Feb 2020, 11:44 pm   #95
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Default Re: 1938 Murphy A56V television restoration

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Originally Posted by Catkins View Post

I did think about writing a BVWS article last year
Hi Catkins,
Glad to see you are still persevering with this project even though you have not had any time to devote to it. Hope your life settles down a bit soon and things get a bit calmer for you.

I always enjoy reading your latest instalments and the whole restoration would definitely make a great BVWS article. The BVWS Bulletin is usually sadly lacking in TV related material, although the editor can only print what we, the TV loving people submit. I'm just as guilty- I really must finish the articles I started several years ago!!

Keep at it and good luck,

All the best
Nick
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Old 22nd Feb 2020, 5:22 am   #96
Catkins
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Default Re: 1938 Murphy A56V television restoration

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Excellent result! And nice to see a RACS CRT in operation.

Peter
Thanks Peter,

I put a video on youtube with the rebuilt CRT here https://youtu.be/QmU8_tkQ_z4

If you compare it with the video I previously made (with an original CRM92), it has much better brightness and contrast https://youtu.be/8XaaeC7idIQ

That CRM92 is the best I found after buying a number of televisions with a CRM92, just to get the tube. Though it is not obvously low-emission, I would say it is showing signs of deterioration, as it isn't really bright enough to view without being in darkness. But, as usual, without seeing a NOS tube it is difficult to know.

I also put a brief clip of the rebuilt CRT showing Dr Who (Patrick Troughton, The War Machines) here https://youtu.be/I2A7mzmsGx8, to make a change from above 1946 film.
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Old 22nd Feb 2020, 2:45 pm   #97
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Default Re: 1938 Murphy A56V television restoration

Very good focus and video bandwidth and a nice stable picture. What are you using to video off the screen? You have managed to avoid any aliasing effects very well.

Peter
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Old 22nd Feb 2020, 2:56 pm   #98
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Default Re: 1938 Murphy A56V television restoration

Fabulous. Murphy owners wanted for little in terms of quality more than eighty years ago. You have captured the detail in the darker areas of the picture well.

Steve
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Old 23rd Feb 2020, 6:15 pm   #99
Catkins
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Default Re: 1938 Murphy A56V television restoration

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Very good focus and video bandwidth and a nice stable picture. What are you using to video off the screen? You have managed to avoid any aliasing effects very well.

Peter
Nothing very exciting I'm afraid, just a normal Canon Digital Camera (PowerShot SX720 HS).

Phillip
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Old 23rd Feb 2020, 11:41 pm   #100
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Default Re: 1938 Murphy A56V television restoration

Thanks Phillip,

My SD Sony DV palmcorder does give quite reasonable alias free recording using digital slow shutter but I haven't had the same alias performance using slow shutter on a more recent Sony HD palmcorder nor on a Panasonic TZ100 HD camera.

Peter
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