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Old 13th Jan 2020, 2:31 pm   #61
Luxman1050
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Okay readings taken.
DK96 DF96 and DAF96 are all 0.3v lower than specified.
DL96 is 0.6v lower than specified.

R15 quoted 5.6v I'm getting 3.22v so 2.38v lower. I would have expected that to have been a lower loss say 1.5v.

Mains has gone up 1v now 146v.

MR anode to anode 82.8v should be 84v so only 1.2v difference.

So all in all considering these are battery type valves I think the readings are good and I don't think it will cause any problems with the operation of the radio and should not affect life span of the valves.

I could mess around with R20 but that's gonna affect the current as well as the voltage so I think I'll leave it alone.

Cheers Chris
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Old 14th Jan 2020, 12:58 pm   #62
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Well here we go another one. The layout on this is different.
Does that mean it's an older model or newer. R19 has the contact more or less at the farthest end? R20 is plastic but is a 4 watt resistors not come across this before.
The metal rectifier is on bottom of chasis as you can see in the way of the sliding R19 resistor. This is supposed to be mounted behind the mains transformer ontop of chasis? Plus it has lots of blue tape over the contacts.
On top the output tranny is facing in towards the speaker as opposed to the front which makes it harder to get to the capacitor. The speaker is different instead of Celestion it's an R&A it also has a screw in middle so is it a moving magnet speaker.
The guy powered it up with this power cord very safe!!!! and said it works but just static on tunning. Looking at air cap you can see some of the fins are badly bent which would explain that not sure how to bend those back and not sure how it got bent?
It does not look like anyone has touched it as all solder joints have the original red dots.
I'll test everything try and make that fin right and fire her up slowly on variac see what happens.
Just noticed the mains transformer has been touched the rear screws are missing which would explain why the Metal rectifier is under chasis. Plus the waxed paper is buldging out a bit where the white lead goes in think that's main tap.
Wonder why?
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Old 14th Jan 2020, 12:59 pm   #63
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Default Re: Pye CB01X4T (P131MBQ) portable radio

3 more pics
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Old 15th Jan 2020, 12:09 pm   #64
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Wound her up on the variac for 6 hours nothing popped did not take any readings although V3 was red plating at 240v.
I put this down to R20 more or less being fully open. So measured ohms on other radio and set this to same ohm rating. Much better. But! I removed some thick insulation off the MR as I could not get to the terminals. Reading 97v which is 13v higher than should be plus I was getting a loud pulsating thud through the speaker and on moving the MR cables it seem to reduce or increase the thud.
Now is it failing? Or is it because the wires are more or less touching R19? Bearing in mind that it should be ontop of the chasis behind the mains transformer.
Also I could change the MR for resistor and diode but the flying leads are both going into the primary of mains transformer. So those would need to be connected to those two leads as I cannot just solder them together asking for trouble. Or I could move the MR back behind tranny and see if that stops the thudding.
Any thoughts?
Cheers Chris
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Old 15th Jan 2020, 9:14 pm   #65
Simon Gittins
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Hi Chris,

Quote:
The speaker is different instead of Celestion it's an R&A it also has a screw in middle so is it a moving magnet speaker.
It's just a normal moving coil speaker, moving magnet ones are in much older sets and have an adjusting screw on the cone side.

Quote:
Looking at air cap you can see some of the fins are badly bent which would explain that not sure how to bend those back
The answer is with difficulty and a lot of patience! Resistance checks should confirm whether it's no longer shorting.

Quote:
V3 was red plating
I've not seen this in a battery mains set; voltage checks should narrow it down, could be a problem with R11.

Quote:
I put this down to R20 more or less being fully open.
I'm confused here; R19 is the adjustable resistor and shouldn't normally need adjustment.

I'm not sure about the other points you mention; sounds like you are making progress anyway.
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Old 15th Jan 2020, 10:42 pm   #66
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Thanks for reply.
R19 is usually set just under halfway usually but on this set it looks like they moved it down as far as possible to fit the Metal rectifier in next to it. So I thought that could have thrown the voltages out and V3 is plating well I say plating you can actually see it glowing even in daylight. My other one has no sign of it lit at all even in the dark. But I have not checked all voltages yet as that thud concerns me.
I've moved the MR back behind the mains transformer but where they moved it they had soldered extra bare wire onto the flying leads. Not sure that's a good thing to do since there on primary winding.
I'll do some checks tomorrow but I think all caps 0.001uf and above will need changing and some of the resistors that should get the current down on V3 hopefully.
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Old 18th Jan 2020, 5:38 pm   #67
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Any ideas on equipment for re tunning the RF signals on radio sets had a look around but seems to be too much too chose from. I know you need to send signal through the radio and alter frequencies as you go that's about it. I've Never tried it before but would be interesting to give it a go.
Oh has anyone got any dials for this radio was offered three but need 4 and thought ones offered were bit pricey. Could be wrong but would have thought couple quid each.

cheers guys.

Oh Lawrence those sites you passed on have been great help thumbs up on that one.
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Old 20th Jan 2020, 4:59 pm   #68
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Well not really related but by now I think you all know I waffle on a bit.
Anyhow bit excited I picked up 5 portable radios today 2 pye 2 marconi and a vidor.
Well what a surprise when I opened one the original ever ready batteries where still in the pye set as new with plastic wrapping still on one the one with the worn dials.
One is 1.5v reading 1.36v and 90v reading 82v. Wow no leakage at all.
Are they any good?
Anyhow I think I done okay for 15 quid the lot. Definitely keep me busy for a while which is good as not been feeling too well lately so not getting out much.
Pics attached.
All best Chris
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Old 20th Jan 2020, 5:19 pm   #69
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Default Re: Pye CB01X4T (P131MBQ) portable radio

I suspect the batteries will now have a high internal resistance and be unable to supply much current. But it is worth carefully taking them apart and keeping the cardboard outer (which looks to be in excellent condition) and the socket connectors to use to make new batteries. The 1.5V one is 2 cells in parallel, modern D cells can be used (they are physically smaller than the originals). The 90V one is 4 stacks of 15 layer cells in series (60 cells, 1.5V each), I think you can just fit 10 PP3s in there.
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Old 20th Jan 2020, 6:47 pm   #70
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Quote:
Originally Posted by telstar View Post
Yes this is a really nice radio. The plastic clad wire that links the frame aerial to the radio had suffered badly on my example and was replaced with the type of coloured wire that you can buy at the N.V.C.F meetings (it does not look too bad).
Cheers
Mike
Hi. The N.V.C.F meetings are held usually in May to sell vintage radios and spares. See the website for details.
Mike
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Old 20th Jan 2020, 7:16 pm   #71
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Yeah I'll do that Mike.
The batteries are like new one still has the plastic covering on it.
Post few pics of condition.
If you pull them apart won't you end up damaging the packaging and would you be able to salvage the connectors? Or end up breaking them?
Would that also affect their value and collectability?
Just random thoughts.
Cheers Chris
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Old 21st Jan 2020, 10:31 am   #72
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Hi,
The battery cartons will come apart fine, provided you have patience and take care. Try to separate the joints using a flat knife or something similar. You just have to work the knife in slowly to split the glue - feeling what is happening as you go. The B126 will hold two stacks of five PP3s taped together. You can get 10 off good quality alkaline ones on ebay for about £10. Care is needed when soldering the PP3s - you have to be quick otherwise you can damage them.
The AD35 will take two D-cells as mentioned, but I prefer to use two C-cells instead. That way, you can fit them in twin C-cell battery holder re-wired to put the cells in parallel rather than in series. No need for soldering when you change the LT batteries this way! The battery sockets are quite sturdy, so no need to worry about breaking them.

Colin.
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Old 21st Jan 2020, 4:13 pm   #73
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Okay guys I'll give it a go so it's connected as positive to negative across all terminals then fit the socket at the end of the chain. So series will increase volts but current remains the same if parallel voltage reduces but current doubles think that's correct.
Cheers Chris
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Old 21st Jan 2020, 5:15 pm   #74
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Default Re: Pye CB01X4T (P131MBQ) portable radio

When you come to try and straighten the tuning capacitor vanes, disconnect the wires from both sides of the fixed vains and use your meter on continuity. It really helps if you have an audible warning on the continuity range as it responds to shorts better than the meter which is often slow to react.
Its always a good idea to keep the vanes fully closed when working on a chassis to prevent this sort of damage.

Mike
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Old 21st Jan 2020, 7:39 pm   #75
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Cheers Mike.
I'm going to remove it from the chassis so should make things easier still not sure what to use to straighten them. Was going to use needle nose pliers.
I have decided to do a complete strip down on this one remove volume pot clean carbon tracks, remove switches and deep clean contacts add a new tuning cord, clean up the chassis change all resistors and capacitors except the ceramics as I don't want to mess up the tuning and complete re wire and all solder joints re done. I know some prob think it's a waste of time but will be interesting to see if reception and sound reproduction will improve. I mean wire over 80 years old has got to have become brittle, degraded insulation and lose its inductance ability just like other components degrade.
Plus it's a good way to learn why this was put there and that over there etc.
Cheers Chris
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Old 22nd Jan 2020, 11:41 am   #76
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Hi guys quick question C25 0.5uf 350v cap attached to pin 7 on V1 then chassis ground. Now that's the heater and only produces couple volts so does the replacement have to be 350v or can I put in a 200v cap. Not sure why voltage so high to be honest.
Oh pic attached of fully cleaned volume pot. If you do this make sure the contacts on the track are turned carefully as the carbon track has a gap at ends and if you force it the wrong way you will break the contacts. Just for reference.
All best Chris
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Old 22nd Jan 2020, 12:27 pm   #77
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Hello again,
My approach would be 'if it ain't broke don't fix it!' Check that the big resistors (anything over 1Meg) haven't drifted too high by all means and maybe change any that are more than 20% out. Waxed caps can go leaky and pass current. A good test for those that go from HT+ to ground via a resistor is to connect up the HT with a mA meter in series but leave the LT off. There will be no current through the valves so any that is flowing must be flowing through a cap. Lift one end of each in turn to determine which one.
Of course the one waxed cap that I would change is the one passing the audio from V3 anode to V4 grid - any leakage here will put positive volts on V4 grid, the valve will quickly be ruined due to passing excess current.
The problem with mass component changing is that you risk importing extra faults or causing damage to other components. If soldered joints look shiny, just leave them as is.
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Old 22nd Jan 2020, 1:20 pm   #78
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Thanks for info all caps have drifted high as previous one. As had alot of the resistors. Just wanted to know if C5 can be changed to a 200v instead of 350v insitue at present.
Yes I can see what your saying re damage unfortunately when soldering these back in the day the wire, caps resistors etc are all wrapped around the tags and cut tight. Instead of that I cannot understand why leaving an extra piece of wire slightly protuding so when heat is applied you just lift was not the thinking. At least then it's brief heat contact to solder lug hence components don't get overly heated up and melt wire insulation.
There's not much in the way of components and wiring to change on this once stripped down very basic. But I do not intend to remove the ceramics on IF RF stages as lessons learnt on that one whereby no stations could be picked up dead as a door nail and I don't have the equipment to return although it is something I'd like to try.
Cheers Chris
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Old 22nd Jan 2020, 3:03 pm   #79
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Forgot to say as previously written further up the thread your right re V4 V3 as I wound her up on variac up to 240v and V3 was actually glowing which is not norm for these valves so I put another in and exactly the same. So your spot on there.
Plus output into the speaker was causing a loud thuding whether their related not sure. But V4 and V3 feeds the output so it would suggest problems there.
All interesting stuff.
But if anyone can confirm if c25 can be 200v would appreciate it as it's only fed from S2a going to LT- HT- via S3.
Thats how it looks on schematic although there might be a slight feed from the secondary via S2B.
cheers Chris
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Old 22nd Jan 2020, 8:27 pm   #80
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Default Re: Pye CB01X4T (P131MBQ) portable radio

Nice cleaned up switch for bands. Was filthy but has come up a treat.
Removed tuning cap and as you can see not that well though parts of the vanes are actually sort of chipped looks like a screwdriver or something had slipped there! I thought of filing the chips out but my worry is all the small fragments getting inbetween the vanes causing more problems! Any thoughts on how to tackle this one?
Chasis now looking bare. Looks nice and clean in pics but is not.
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