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Old 17th Jun 2019, 7:26 pm   #61
stofbj1
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Great finally figured out that the cap (black) I could not read is c51, its going to ground on one end, to a 0.22M & 0.1M resistor R5 & R28.
So the film caps I will need are
2 x 15000pF (0.01uf) for C52 & C54
1 X 2200pF (0.0022uf) for c47
1 X 100nF (0.1uf) for c51

I will empty the main filter cap can and install two 50uF electrolytic inside, connect the two negatives together and solder them onto the outside can, this should do for this.

And then cross fingers and toes
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Old 17th Jun 2019, 7:49 pm   #62
Maarten
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Default Re: Help to identify old Philips valve radio. BIF 571A.

The main filter might not need replacing.

If you decide to restuff it, make sure the new capacitors can withstand the ripple current. Many modern parts don't. You'd be looking for the very long, narrow ones used in LCD TV power supplies, or the short stubby ones with snap in pins. Even then, make sure to have a look at the datasheet first. The 100Hz ripple rating should be somewhere in the range of 300-500mA if I remember correctly.

Quote:
Originally Posted by paulsherwin View Post
It does look as if Philips Ireland just took the 353A chassis and built a nice wooden cabinet for it, adding a magic eye. I wonder if Philips GB had stopped production by then and had some surplus parts and tooling.
I noticed in the service manual that lots of key parts - including the cabinet - have Dutch part numbers. This fits into the idea that the set may have been partially based upon some Dutch export or CKD model. Models that often didn't have FM, so the addition of a British FM part makes extra sense within that context as well; in any case the FM tuner looks very non-continental, so that may have been one of the British surplus legacy parts.

Last edited by Maarten; 17th Jun 2019 at 8:00 pm.
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Old 17th Jun 2019, 9:23 pm   #63
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Unless I've missed something, why are you changing capacitors willy nilly?

The first check must be if there is any DC on the grid of V6 it should not be positive. If it is hook in anything from 0.01uF to whatever @ 300vdc working.

Move then onto HT, then V5a and V6 anodes. The schematic will tell you what should be there. If there little or no hum from the speaker and the HT is OK, the main smoothing is probably OK. No need to stuff anything.

Should these be within spec, the cathode bypass C3 would be my next choice.

The loudness capacitors are unlikely to be short circuit
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Old 17th Jun 2019, 10:01 pm   #64
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Default Re: Help to identify old Philips valve radio. BIF 571A.

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Unless I've missed something, why are you changing capacitors willy nilly?

The first check must be if there is any DC on the grid of V6 it should not be positive. If it is hook in anything from 0.01uF to whatever @ 300vdc working.

Move then onto HT, then V5a and V6 anodes. The schematic will tell you what should be there. If there little or no hum from the speaker and the HT is OK, the main smoothing is probably OK. No need to stuff anything.

Should these be within spec, the cathode bypass C3 would be my next choice.

The loudness capacitors are unlikely to be short circuit
Will nilly, capacitors that are 70 odd years old, I don't think so, as already stated they measure ok, but are probably leaky at this stage, and for the sake of the cost of 4 film capacitors, it's a safe bet to do, for not only safety reasons, but for preventing future failures. I think the main power filter cap is OK and I will leave this be for now, there is no hum or buzzing. When the caps have been replaced, then I will safely take voltage readings without damaging any further components, i.e valves. " The schematic will tell you what should be there" not the one I am looking at, no voltages given. "The loudness capacitors are unlikely to be short circuit" as already stated if you read through the thread, none are shorted or open circuit for that matter. But possibly leaky.
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Old 17th Jun 2019, 10:03 pm   #65
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Default Re: Help to identify old Philips valve radio. BIF 571A.

The voltages are in a table on another sheet of the service manual on RM.
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Old 17th Jun 2019, 10:17 pm   #66
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Default Re: Help to identify old Philips valve radio. BIF 571A.

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The voltages are in a table on another sheet of the service manual on RM.
Great thanks for that, I will have to wait till tomorrow, as I have reached my 3 download limit.
Just in the process of ordering some Axial vishay film caps (rated at 630v). Will update the post when installed, and hopefully that is the issue, if not I will take some voltage readings.

Regards
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Old 17th Jun 2019, 11:32 pm   #67
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Philips Black wax coated capacitors can fail but they are not Hunts which should be changed on sight. My message was not to belittle you but to help you narrow down the fault.

Should you feel you should change all before checking the DC levels, don't forget C55.

Good luck

Chris
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Old 17th Jun 2019, 11:41 pm   #68
Maarten
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Default Re: Help to identify old Philips valve radio. BIF 571A.

The black ones WILL fail sooner or later as they are molded impregnated paper capacitors, but indeed they won't be as bad on average as the hunts, ero, wima or rifa ones.

That said, it would make sense to replace "that" capacitors on sight, and replace the others only after a bit of troubleshooting - if only to prevent introducing new failures.
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Old 19th Jun 2019, 10:55 pm   #69
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Hi all,
Just an update, I got the new Vishay film caps today and replaced them all, and it sounds much better now, before the sound would start drifting away and sometimes come back, which is now fixed. It's still not super loud, but I have never heard one of these, So I do not know what to expect'(I do have a valve BUSH record player which goes a lot louder). Anyway I have oiled and re lubricated all the moving parts, to prevent the tuning cord from snapping. I have not taken an voltages, as I am already over the moon with even getting sound out of this. Thanks everyone for your help with this, It's nice to get it going and hopefully prevent any future failures to the valves. Oh "simpsons" no offence taken by the way. I had the Hunts in my Bush record player, they were bad alright.
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Old 20th Jun 2019, 12:28 am   #70
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Default Re: Help to identify old Philips valve radio. BIF 571A.

It should go louder than you'd want.
Still, good progress.
PM me if you are ever heading to Limerick, I'm on the "Killarney" side outside the city.
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Old 22nd Aug 2021, 1:19 pm   #71
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Thread reopened by request.
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Old 22nd Aug 2021, 5:35 pm   #72
Tony De Frego
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Thanks for re-opening this thread guys. I recently bought one of these BIF 571A radios and I am doing my homework before I tackle it. I have a few questions and, given the responses already in the thread from others previously, I think it's better to re-open than to start a new thread.

Firstly, I'm from the world of valve guitar amplifiers where it's pretty much a given that old electrolytic caps are changed out if they're over 25ish years old. I've downloaded the schematic and taken a look. The one in here is a 50+50 Dublier. I've read about "screw top" cap cans over on one suppliers page. I've never heard of screw stop caps. Some people seem to talk about "re-forming" old electrolytic caps. Is that the thing to do in radios? How safe is it?

It's also pretty standard to put three prong plugs on old valve amps like fenders and to remove the "death cap". I suspect it might be a can of worms topic... but is that something that you'd do to a vintage radio? I'm going for safety in preference to keeping the radio stock. To be honest I'm still getting to grips with the ground scheme in the radio. The chassis is the ground here from what I can tell... so does that mean that the neutral from the plug (as opposed to the live) is hooked up to the chassis? Forgive my beginner questions here. I see that the centre tap on the Power Transformer secondary seems to be connected to the chassis. Anyway... I think that is knowledge that many people will have in here and might be kind enough to clear it up for me. In short... if I put a three pronged plug on it and connect the earth to the chassis... do I have to disconnect the neutral from somewhere?

Anyway... I get sound from the radio. RTE1 comes in on AM and the tuning knob does very little to change it. The guy I bought it from had it plugged in when I arrived to pick it up. I've since turned it on and taken a few voltage readings from V6, V5 and the HT... which match the schematic... so that's good. The schematic is a bit weird in that it shows the FM section but that bit has no details on the layout further down. As a result, I haven't been in at V1 or V2 yet. I'll take it all apart later and see what the voltages read and compare them to the schematic.

People earlier in the thread have spoken of the tone knob. I guess that's the middle left of the four knobs. It doesn't do much at the moment. I was wondering if it was a tone or whether it might be a volume knob for the external record player that can be hooked up at the back. I need to have a closer look at the schematic.

All in all I think it'll be an interesting project and I hope to learn loads. I've never seen many of this type of valve before... and they seem to be standard in old radios.

Thanks in advance,
Tony
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Old 22nd Aug 2021, 6:25 pm   #73
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Neutral isn't connected to the chassis. It goes to one side of the mains transformer primary.

Most people would fit a 3 core cable and earth the chassis. It does increase stress on the transformer insulation, but the safety benefit is worth it.

This is a relatively complex radio for a beginner - concentrate on getting MW/LW fully working before looking at the VHF stuff.

If you have powered up the radio and it 'works', then you probably don't need to reform or replace the reservoir/smoothing electrolytics, at least at this stage.
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Old 22nd Aug 2021, 6:36 pm   #74
Tony De Frego
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Default Re: Help to identify old Philips valve radio. BIF 571A.

Quote:
Originally Posted by paulsherwin View Post
Neutral isn't connected to the chassis. It goes to one side of the mains transformer primary.

Most people would fit a 3 core cable and earth the chassis. It does increase stress on the transformer insulation, but the safety benefit is worth it.
I guess I am not clear on where the ground comes from when it's just a two pronged plug.
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