Bush VHF61

[Steve G4WCS]

Ive had a set sat in the garage for a good few years now. I did restore a few sets years ago and had a working one but can’t remember whether I went through it or it was just a cosmetic restoration. What sort of job are they to go through, is it a re cap job or do they have their own foibles ? (Its got an em81 fitted but I did but some em84’s so I wonder if that needs replacing ) tia

[bobhowe]

Hi Steve read my thread about my Bush VHF 61 i only changed C56 on the trader sheet available to download from this forum . Be careful with the wires on the furrite aerial kind regards Bob

[Glowing Bits!]

Usually I go for a waxy cap replacement on these things, the micas don't need touching.
Resistors are pretty much the same as micas except the output cathode, this should be checked with a meter then go from there with it.
Electrolytic can would usually benefit from a reform but is likely to still work, it's made by either Plessey or TCC so it's quite reliable, unlike Sprague & Dubilier stuff.
Wiring won't usually need anything doing to it as it's PVC, unless it's damaged.
These sets are good on AM but seem to be a bit useless on FM.

[Techman]

Sorry Rick, I can't agree with you on that one. I've got one of these sets and I can tell you that it's the other way round regarding performance with FM being stunning and AM being what you would regard as being acceptable. Also, I agree with Bob regarding not needing a mad capacitor swap out, with just the critical ones needing replacing with the most important one being the mentioned 'grid coupling (that) capacitor'. When I did mine a few years ago I possibly replaced a couple of capacitors in total - I can't remember without checking, but there's a thread on this particular set on the forum somewhere, so I'll have to try and find it to check exactly what I did.

It's a well known fact that these sets perform better on FM than they do on AM and if it's not performing top notch on FM then there's still an undiagnosed fault, possibly even caused by the unnecessary blanket replacing of all the capacitors, which is one of the main reasons that I'm strongly against it! Bad FM performance is usually due to a weak ECC85 in the FM tuner.

Really bad AM performance, particularly with dropping out on long wave is usually caused by a failing ECH81. Generally poor performance is often due to a low emission EZ80 rectifier, so remember to check that HT voltage.

[Techman]

Originally Posted by bobhowe

only changed C56 on the trader sheet

I just found my old thread from May 2015 (was it really 6 years ago) and it documents all the faults I mentioned in my above post and it seems that I did just replace the one capacitor, which I noted as being C65 on the trader sheet, so one of us has got the wrong part number written down!

The radio is still working faultlessly six years on and I'm looking at it now, stood on top of the piano as I type this post...that's the radio, not me!

[Techman]

I had in the back of my mind that I actually did do some more work to the radio than I documented in the thread at that time. I seem to remember looking at the AGC line and trying to possibly improve the performance on AM and also the magic eye performance on the same mode, which is a well know issue on these sets, performance of the eye being good on FM. Having found a date for when I worked on the radio, I've now found another photo showing that I did replace several more capacitors in the set at that time. I seem to remember that very little difference, if any, was observed. Finding that picture saves me dismantling the set again to verify what I actually did, but didn't get round to fully documenting in the thread - picture below, lucky I took it:-

[Nickthedentist]

Change all the Hunts Mouldseals (sorry, Techman!)

Re-form the BEC dual electrolytic.

Replace the discriminator electrolytic, observing correct, counterintuative polarity.

Check the Rs are approximately correct, esp. the 180R one on the EL84 cathode. You can shunt the latter to bring it down to the correct value if you prefer (Leon's tip).

I fit a 3-core mains lead because that's what I prefer to do with AC sets, but we all know what a minefield that is!

There may be perished VIR wiring to the magic eye, scale lamps and speaker which would benefit from being replaced.

The eye will probably be dim. An EM84 will work beautifully with minimal mods, though looks wrong.

Polish the Bakelite case in the usual way.

The grille cloth can be washed, but the hardboard baffle doesn't like getting wet (guess how I found that out).

Performance on FM will be super, but fairly mediocre on AM.

Nice reliable, easy to service sets, slightly let down by the smallish, single speaker and plastic case. The VHF62 sounds a little better. And then buy yourself a VHF64/94 if you want the real deal.

N.

[bobhowe]

Hi i agree with Techman my set is great on FM and the magic eye been good on FM good luck with the set you will be pleased with it when it is working properly kind regards Bob

[Techman]

Originally Posted by Nickthedentist

Replace the discriminator electrolytic, observing correct, counterintuative polarity.

Yes, if you look closely at my picture, you'll note that I replaced that same capacitor in my set - I seem to remember that it actually made little, if any difference, as the set was already performing and sounding well on FM, but I will agree that being a small value electrolytic that it can degrade with time and is a known issue in some sets of that same era.

For those that really must insist on stripping out and replacing ALL the original capacitors, I seem to remember that you produced a very comprehensive shopping list on a spread sheet I think it was, in a thread many years ago. I have to say that it was a rather good and thorough list for those that like to perform this operation, even though I don't agree with doing it as such. However, not all radios are the same and some will require more work than others. I'd like to put my set next to yours, Nick, and compare the performance side by side - I bet there'd be no difference, although I've somewhat spoiled the comparison by going on to replace several more capacitors in my set. You can clearly see the remaining Hunts capacitors in mine in the chassis underside photo I posted...and it performs just fine!

[Steve G4WCS]

Cheers all. Lamp limitered it then brought it up to full mains. Vhf and lw seem ok. Nothing on mw. Ill give it a going through and cosmetic refurb

[bobhowe]

Hi Steve Please check the black wires from the furrite aerial to the tag strip on the chassis has not come away & clean the wave band changing switch i have only replaced 1 capacitor C56 & 2 missing valves and is working great after i found the loose wire preventing it from working on MW kind regards Bob

[Nickthedentist]

Originally Posted by Techman

Yes, if you look closely at my picture, you'll note that I replaced that same capacitor in my set - I seem to remember that it actually made little, if any difference, as the set was already performing and sounding well on FM, but I will agree that being a small value electrolytic that it can degrade with time and is a known issue in some sets of that same era.

For those that really must insist on stripping out and replacing ALL the original capacitors, I seem to remember that you produced a very comprehensive shopping list on a spread sheet I think it was, in a thread many years ago. I have to say that it was a rather good and thorough list for those that like to perform this operation, even though I don't agree with doing it as such. However, not all radios are the same and some will require more work than others. I'd like to put my set next to yours, Nick, and compare the performance side by side - I bet there'd be no difference, although I've somewhat spoiled the comparison by going on to replace several more capacitors in my set. You can clearly see the remaining Hunts capacitors in mine in the chassis underside photo I posted...and it performs just fine!

Yes, I would like to do a comparison too, and I suspect you're right that there would be little if any difference at the moment. But what about 10 or 20 years down the line when the remaining Hunts have gone from bad to worse? Again, I'm not convinced one way or the other, but I prefer to do the lot once I'm in there; the extra cost involved is minimal, and as I'm generally an accurate and quick worker, I think my way is quicker for me. But yes, some of the originality is lost, and a useful learning experience is missed.

P.S. Glad you liked the spreadsheet! I used to do that thing when I had more time on my hands, but I can't say that I've done anything similar recently. Life seems to get busier, I seem to get tired more easily....

[bobhowe]

Hi Nick not been in the TV & Radio trade it is a learning curve for me and i am enjoying it as a hobby any not done too many mistakes ( yet ) Kind regards Bob

[Nickthedentist]

Me too, I'm a dentist by profession, 99% of the rest of my time is spent doing stuff with/for our three children, but just occasionally, I get to play with old radios.

[bobhowe]

Hi Nick it amazing how many people on this forum are not in the trade . That has give me an idea to start a new thread kind regards Bob

[Techman]

Originally Posted by Nickthedentist

P.S. Glad you liked the spreadsheet! I used to do that thing when I had more time on my hands, but I can't say that I've done anything similar recently. Life seems to get busier, I seem to get tired more easily....

Yes, I thought I'd have more time when I retired from work, but it doesn't seem to be the case, and I too seem to get tired more easily, probably I've let myself get more 'timeless' and less organised than when I was at work...and of course I'm older, but still manage to make time to get out on the old (vintage) push bike now and again!

Regarding original capacitors 20 years down the line, It's a good question, but you have to remember that many of these capacitors are under no stress regarding having any voltage as such across them, so mostly I suspect that they'll probably be fine - a lot depends on where they are in the circuit.

I remembered something else regarding the extra capacitors that I replaced in that set and that was that certainly one of them I accidentally damaged while poking around in the chassis (its plastic case broke and fell apart), so I had to replace it for this reason. I also note in that picture that I can just see the edge of the square power resistor that I fitted in series with the silicon rectifier diodes that substituted at the time for the EZ80 valve rectifier and soldered to the underside of the base with the valve of course removed, as I'd run out of replacement EZ80s. I remembered that a while later I was able to stock up with replacements from a junk sale, so removed the chassis again to remove the bodged temporary rectifier from beneath and fit a proper EZ80 valve rectifier - not that there's anything wrong with replacing a valve with silicon (many radios do this - Grundig etc.), but I like to keep with originality and it's kinder to the smoothers.

Wax coated capacitors I think we probably all agree are particularly nasty, just purely because they're messy and sticky. I've got to confess that I replaced one just on the basis that the stickiness was getting all over my fingers, meter probes and tools while I was trying to work on a chassis and was making a right old mess, so I seem to remember that I replaced it and possibly another equally messy one next to it - now that's bad and not conducive to keeping with originality...I just got annoyed with it at the time, the plastic cased Hunts are so much cleaner!

[Aubade65]

Just to wade in on the Great Capacitor Replacement debate.

A number of the capacitors are used for both AGC and screen grid decoupling so any fall off in the efficency of these parts can have a big effect on performance.

I too have often found the plastic cases to be cracked and falling apart so I tend to replace them en-masse normally with little green mylar ones that do not seem to be out of place in this setting. I seem to recollect that are something like a dozen to be replaced ( some are quite well hidden around the ECH81), leaving the VHF tuning head alone unless there is a proven fault there but that seems to be quite rare.
I do not think that I could face having to put the set in the right position, connect the test equipment etc, etc to test it after replacing each cap although I can see that if the set had an obvious fault with the performance well down it would be educational to see where the fault was if it was coupled with a well thought out fault finding process.

[Nickthedentist]

My VHF 61 looked like it had lived in draughty, damp loft for a few decades; the aluminium chassis certainly had some whitish pitting and the ferrous bits had superficial rust. All the plastic-cased Hunts caps had split, which certainly made me keener than usual to replace the lot.

But maybe on a basically-working set that had been in-use until recently and always kept indoors, I might have felt differently. I have an Ekco U243 (similar era) which I bought when I was student in the 1990s. It was immaculate and sold as working, and indeed I suspect the original owner had been using it one day, passed away the next, and it had ended up in the house clearance shop a few weeks later. Not knowing any better, I just checked the mains plug and used it in out student kitchen for a few years. And yes, its performance seemed every bit as good as one I did a full de-Hunts on recently, but this particular one had definitely suffered from damp storage, with the paint peeling off the speaker, some worm, and a slightly flakey dial glass.

[PaulR]

I did one of these years ago and followed the route of diagnosing the faults the replacing the appropriate components - usually Hunts caps. It would work for a while then another fault would develop.

I decided to go down the route of a full re-cap and it has worked well ever since.

By contrast a friend asked me to repair a Murphy (I think) set of a similar age. I replaced just the audio coupling and tone correction caps, I expected it to come back for the rest of the Hunts caps to be done but about 10 years later it is still going strong. I wonder whether the seal on some batches was a lot better than on others.

[bobhowe]

Hi Paul you could be right there about Hunts capacitors my Bush VHF 61 must have been owned by a chain smoker as it was full of cigarette tar cleaned the insides with a soft paint brush and it looks like new even the Hunts capacitors are not cracked wonder if it was the cigarette tar that has preserved them kind regards Bob