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Old 10th Jun 2019, 1:04 pm   #21
Welsh Anorak
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Default Re: Alba TC1525 G6 Dual Standard.

What if this someone has found no 12v and gone looking for a likely source, finding it in the feed to the relay or brightness circuit? Now you've restored the correct source you might be feeding it back to where it shouldn't go! Only speculation, of course. I'd be tempted to have a long look for poor soldering or non-Philips wires.
The best of luck!
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Old 10th Jun 2019, 2:52 pm   #22
MickMcmichael
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Default Re: Alba TC1525 G6 Dual Standard.

Yes Glyn that's a worthwhile thought which I'll bear in mind.

I'll be taking another look at it later.
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Old 10th Jun 2019, 8:02 pm   #23
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Default Re: Alba TC1525 G6 Dual Standard.

First thoughts are the luminance switch on the CRT panel. It may have been depressed to conceal excessive brightness.
Secondly, have you tried switching off the individual CRT guns(simple to do on the convergence panel). If doing this doesn't kill the raster the prime suspect is the zener diode close to the PFL200. This was replaced by a BC108 transistor in the single standard version.

It must be a highly rated to work reliably, 10W if possible.

That's a nice early example you have there. Shame the system switch has been removed.
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Old 11th Jun 2019, 8:49 am   #24
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Default Re: Alba TC1525 G6 Dual Standard.

Quote:
That's a nice early example you have there. Shame the system switch has been removed.
It was common to link out system switches once dual standard sets were being used on UHF only. Depending on the model I would disconnect the linkage and fix the switch in the 625 position routinely on any sets that I was refurbishing for sale.
On some Philips sets and the Thorn 1400 I would usually fit wire links to the print side of the board if the switch was a bit intermittent.
Why remove the switch completely though? A bit strange that... I can't see it was due to leakage, especially on the IF panel switch. burnt contacts wouldn't matter if the switch was linked and mechanically disconnected.

It looks like someone got a bit bogged down with this and gave up.

Rich.
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Old 11th Jun 2019, 9:12 am   #25
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Default Re: Alba TC1525 G6 Dual Standard.

The plot keeps thickening with this project.

I've had a very kind offer from a member on here for a limited source of parts. I shall persue that in due course. Thank you kindly.

It looks as if the person who took on the job of turning this set into 625 only was damned determined to do so. Solenoid gone, all system switches gone including on line scan and timebase units. Microswitch on tuner gone and ALL 405 convergence controls gone and the 405 section of the convergence guide cut away. The 405 line oscillator coil....guess what....gone!

I also discovered yesterday morning that the luminance switch on the tube base has also been liberated. The brown wire being soldered directly onto the coil on the tube base.

But I have a raster and sound. I really will have to give up on the idea of a fully switchable 405/625 set as too much has gone.

So, instead of looking for things that aren't there, I shall go back to square one and concentrate on the stuff that is there. I will try to fault find it from scratch and hopefully end up with a working colour set.

Keep watching this space!
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Old 11th Jun 2019, 9:50 pm   #26
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Default Re: Alba TC1525 G6 Dual Standard.

That's a shame. The model I had was obtained from derelict but had an equally derelict spare chassis to make one good set from the two.

Usually, when adapting a set for 625 only it made sense to remove the sliders then hard wire. Seems the previous owner of yours went too far and probably introduced faults along the way.

Still suspicious of that zener diode though. When I first got my example working I got a lime green raster on both systems which couldn't be extinguished on switching the A1s off. The zener was responsible.
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Old 12th Jun 2019, 7:44 am   #27
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Default Re: Alba TC1525 G6 Dual Standard.

I removed the convergence box last night and the gun switches work as they should. I can shut the raster off and all three CRT guns seem ok.

One other thing I noticed was the 12v line which I mentioned in a previous post (where the 15k had been removed) was varying. When I checked it was around 18v which was odd as it had been bang on 12v when I fitted the 15k

Further investigation showed that there should also be a VDR in the same part of the circuit as the 15k... now you know where this is going, don't you! Yup, it was gone!

Aarrgh! For the moment I've used a 12v zener and the 12v is spot on.

Some odd voltages around the colour difference drives was my last port of call last night. Obviously with no signals these voltages would be wrong anyway. However, I was intrigued to find that both the red and blue channels to the tube base (R-Y & B-Y) were sitting at 45v but the green was 0v. This simply turned out to be a 10meg anode load resistor R7241 in the G-Y channel. Obviously it made no difference to my other faults but it's another problem solved.

So, carry on for now and I'll check that zener mentioned by Focusdiode. Ta for the tip.
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Old 12th Jun 2019, 10:21 pm   #28
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Default Re: Alba TC1525 G6 Dual Standard.

Hi Mick,
Well done on progress so far. It must be frustrating to find so many hard to come by parts have been removed!, especially when there was no obvious need for them to have been removed!

Very enjoyable write up's too- looking forward to the next exciting instalment!
Good luck with the restoration.

All the best
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Old 13th Jun 2019, 6:30 am   #29
MickMcmichael
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Default Re: Alba TC1525 G6 Dual Standard.

Thanks Nick Hoping to get some more time on it today. It's certainly frustrating going round in circles looking for something that's been snipped out!
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Old 13th Jun 2019, 12:15 pm   #30
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Default Re: Alba TC1525 G6 Dual Standard.

Hi MickMcmichael,

I'm following this with great interest,
I have to "doff" my cap to you here as not only are you fault finding a set that has had many parts removed and with limited data but you are also doing this with probably one of the most fearsome chassis possible!

Just make sure that you get a sane amount of sleep each night and you should make it through to the other side!!

Cheers and all the best.
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Old 13th Jun 2019, 12:59 pm   #31
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Default Re: Alba TC1525 G6 Dual Standard.

Yes following it with interest too.

It was a baptism of fire in my young days when I bought a few from one of those TV warehouses. I had been learning on B/W tvs and thought it was about time I got into colour. ..all those lovely looking ex Visionhire tvs stacked up..there can't be much wrong with them LOL.
However, taking the back off and seeing all those valves and the smoke stack with it's radiation symbol evoked the reaction of OMG!
I soon learned that Visionhire had probably paid the warehouse op to scrap them..not sell them on.
One had curious spots on the screen when on ..I think I came to the conclusion that the shadowmask had shifted.
Some others IIRC had a cherry red PL509 and it's diode and came to the conclusion that a winding had failed..nobody seemed to repair/stock G6 LOPTs
A blank raster source of problem was quickly found by tapping the PFL200 and following the burn marks around it's board.
..but apart from that they did indeed have magnificent pictures once set up with the very convenient convergance controls.
When you switched on and the light in the room dimmed slightly..you knew you had fixed it.
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Old 13th Jun 2019, 4:54 pm   #32
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Default Re: Alba TC1525 G6 Dual Standard.

Same here - As a teenager I bought a '502 for 60 around 1976. As you say, a baptism of fire. After a lot of head scratching as to why there was very little EHT, I looked at another set and discovered the boost capacitor was missing - I'd assumed it was on the paxolin board in the tower as per manual, when in fact it was on the side of the chassis - or wasn't! Replaced it and a great picture appeared. I gave it to my parents and they used it for years till the dreaded LOPT failure....
Turns out that Andrew in the shop (he's a bit younger than me though don't tell him) also learnt on a G6 - he bought one for only a few pounds some years later, but wasn't old enough to drive so he trundled it the two miles from one side of Bangor to his home at the other in a wheelbarrow! Sometimes I think we're all a bit nuts...
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Old 13th Jun 2019, 4:59 pm   #33
MickMcmichael
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Default Re: Alba TC1525 G6 Dual Standard.

Hello Lee and Cheerful Charlie.

I decided just to take a look inside the convergence box. Half of it's naffin' gone!

It sure is a fearsome beast but I will soldier on. A drop of ale sometimes helps!
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Old 13th Jun 2019, 5:01 pm   #34
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Default Re: Alba TC1525 G6 Dual Standard.

Having restored one myself I'm finding the thread of great interest too. The convergence can be set up for amazingly good results on both systems.
Mention of the luminance side reminds me of the delay line itself. Prone to dry joints including at the top accessible pins on the component side. Worth checking for this.

Sorry a previous owner ruined any chances of 405 operation. I was lucky with the example I had. The results are remarkably good on 405 with the shadowmask defocusing the scanning lines somewhat. Off screen 405 photo below. Note the 'blue tinge' feature from the auto white relay!
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Old 13th Jun 2019, 5:52 pm   #35
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Default Re: Alba TC1525 G6 Dual Standard.

It's amazing that these still are surviving and working, given the complexity and potential unreliability - all those watts! I liked the 502 - you could slide the drawer out to do the convergence. All those under-rated wirewounds meant it didn't drift much. Then came the 550 G8 with the convergence panel that resembled a slice of burnt toast after a few years.
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Old 14th Jun 2019, 10:04 am   #36
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Default Re: Alba TC1525 G6 Dual Standard.

I am not sure if it comforting or disturbing to know that Welsh Anorak,myself and other 'nutters' around the isle were all at the very same time in history, trundling these things around with hope in our hearts

I remember a phone call to a rewinder/supplier would go sort of something like this

"I'm looking for a transformer for an early Philips colour set"- "er yes sir, what is it a G8 chassis, if you buy 5 you will get a discount" "er no it's older a G6".....long silence ... "er no sir not much call for them"


Now the baton has been handed to you Mick LOL
I was wondering if the Alba was a budget model? - hence the missing the convergence controls as Philips didn't want their ones upstaged?
Also check the tuner I think it should have a 30v supply in there somewhere but maybe wrong now.
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Old 14th Jun 2019, 10:49 am   #37
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Default Re: Alba TC1525 G6 Dual Standard.

I imagine someone wanted all the bits for his spares box! After all, I doubt Philips would have bothered removing the system switch as well. Probably thought it was a good thing to do, removing the troublesome switches and giving the convergence box more ventilation.
According to the manual, the tuner has two 12v feeds, HT3A and HT8. Goodness knows why!
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Old 14th Jun 2019, 4:49 pm   #38
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Default Re: Alba TC1525 G6 Dual Standard.

Quote:
Originally Posted by cheerfulcharlie View Post
I was wondering if the Alba was a budget model? - hence the missing the convergence controls as Philips didn't want their ones upstaged?
The set would have been built fully dual standard as when it was made it would have needed to work on 405 as BBC1 and ITV were not transmitted on UHF. That didn't happen until 1969 when the first single standard UHF only sets started to be sold.
The Alba brand name was probably just a way Philips could sell outside of the Philips dealer network possibly to small dealers via wholesalers. Thorn certainly did this with the Marconi brand name.
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Old 14th Jun 2019, 5:08 pm   #39
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Default Re: Alba TC1525 G6 Dual Standard.

Quote:
The Alba brand name was probably just a way Philips could sell outside of the Philips dealer network possibly to small dealers via wholesalers. Thorn certainly did this with the Marconi brand name.
Philips sold sets to Alba as another source of income and to improve economies of scale in production. They also had their own wholesale brand at that time: Stella (and dual standard Stella branded G6 sets were produced).
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Old 14th Jun 2019, 5:19 pm   #40
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Default Re: Alba TC1525 G6 Dual Standard.

When did Philips drop the Stella brand?

Pye seemed to take on the mantle of the wholesale brand by the late 1970s.
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