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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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21st Nov 2006, 10:51 pm | #1 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
Posts: 1,023
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PYE 170BQ No LW
Hello,
I'm trying to repair this transistor radio, I now have MW working correctly (replaced electrolytic c12, re connected broken MW coil wire, repair damaged band switch) But I can't seem to get anything on LW other than I can 'tune in' various noises. All trimmers etc. seem to be untampered with, and the LW coil is continuous. I have also replaced the 4 wax capacitors. Any ideas to fix this greatly received. Matty |
21st Nov 2006, 11:26 pm | #2 |
Pentode
Join Date: Aug 2005
Location: Dublin, Ireland.
Posts: 157
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Re: PYE 170BQ No LW
Hi Matt, dont know your model or the precise modules re your set.
I know this might sound basic, but have you checked the waveband switch, or solder connections to same, [dry joint], maybe some switch cleaner, some times its the least obvious things that we overlook. Regards Maitiu. Last edited by Darren-UK; 3rd Aug 2007 at 2:00 am. Reason: Removed text slang in accordance with rule B9. |
22nd Nov 2006, 12:05 am | #3 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,783
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Re: PYE 170BQ No LW
These sorts of problems are almost always caused by problems with the aerial coil and associated wiring, or the wavechange switch. It would be a good idea to double check your work. Sometimes it helps to leave a set alone for a few days - when you come back to it, it's obvious what's wrong.
Good luck, Paul |
22nd Nov 2006, 6:37 pm | #4 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
Posts: 1,023
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Re: PYE 170BQ No LW
Hello, Thanks Maitiu + Paul, I shal have a good look/check over those points. This is such a simple set i can't be anything too major, especially as MW works so well. And yes I'm half expecting the wave change sw as the contacts were bent all sorts of ways when i received it. I will let you know.
Thanks again, Matty |
23rd Nov 2006, 9:58 pm | #5 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
Posts: 1,023
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Re: PYE 170BQ No LW
Hello I've just taken another look at this radio, I've re soldered everything and fully checked the wave change switch. And with some very careful listening i could receive one LW station. I also spoke to the man who owns this radio and he said that LW has never worked, and he has had this radio since new.
As the LW coil was loose on the ferrite rod, i tuned in to the one LW station and moved the LW coil, the station is clearer now and i can now receive a total of four LW stations, alltho they are all very weak. I would re align the set but my signal generator can't be set to a high enough frequency to align radios I can only think that is all that's left to get LW working Does any one have any more ideas? Matty |
23rd Nov 2006, 11:22 pm | #6 |
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Re: PYE 170BQ No LW
You don't need a signal generator to do a basic RF alignment. If the MW reception is OK then the IF alignment is OK, so you only need to worry about the LW aerial and oscillator coils. It's possible that the LW oscillator coil is completely misaligned, and has been since new, though I've never come across this. To do a basic LW RF realignment you should adjust the LW oscillator coil until R4 LW is at the correct position on the dial, then move the LW ferrite coil for the loudest signal. You can rotate the radio to reduce the signal coming in to make adjustment easier. This isn't the ideal way of doing it but it will do a reasonable job.
If R4 LW is still clearly wrong then there is a fault. As I've said, this is likely to be the LW ferrite rod or oscillator coil, wavechange switch, and associated wiring. You should also check for shorts in any capacitors or trimmers which are in circuit for LW and not for MW. Bear in mind that LW R4 isn't particularly strong in Devon and Cornwall. Good luck, Paul |
24th Nov 2006, 10:32 pm | #7 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
Posts: 1,023
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Re: PYE 170BQ No LW
Thanks again Paul, I shal take a look over the weekend
Matty |
25th Nov 2006, 12:24 am | #8 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
Posts: 1,023
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Re: PYE 170BQ No LW
Hello again,
I decided to remove the LW coil from the ferrite rod and disconnect the connecting leads, i then checked for continuity.... one half of the coil O/C That will teach me to check things properly! After gently melting the wax on the coil with a fan heater, I could clearly see one end of wire sticking out, and after a careful look with a magnifying glass i managed to find the other end and slightly free it from the coil. I was very fortunate to have the break just where it was as the coil is sort of weaved and the brake was under several turns of wire. I have now repaired the break by removing a section of the enamel insulation from the ends of the wire and soldering in a link of fine wire. I now have continuity on all three terminals on the coil. I have attached a pic of the repair (bodge ) which is sticking out of the left of the coil. I shal try the repaired coil tomorrow. Is this repair acceptable or should i insulate the two joins (with varnish or similar?) and seal them back in wax? Thanks again, Matty |
25th Nov 2006, 2:01 am | #9 |
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Re: PYE 170BQ No LW
I wouldn't be too worried about whether this repair is 'acceptable' or not. This sounds like a manufacturing fault, so any repair is acceptable, especially if it is reversible. Congratulations on finding the fault - I told you it would be the coil! Test it, and if the repair is sound and well made, leave it alone. That's what a good repairman would have done in the 60s and 70s, so you're making a 'period repair'
Paul |
25th Nov 2006, 12:39 pm | #10 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
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Re: PYE 170BQ No LW
Hello Paul,
Thanks once again, tried today and it works!! and rather well for such a small radio. I just have to reassemble properly now and replace the broken battery holder. Time for a cup of tea i think Cheers, Matty |
25th Nov 2006, 4:07 pm | #11 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
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Re: PYE 170BQ No LW
One final post, i thought I'd put here a post of the final fully working product which is sat here playing.
Cheers, Matty |
25th Nov 2006, 5:04 pm | #12 |
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Re: PYE 170BQ No LW
Oh, it's one of those! My parents had one in the early 60s, I think it was their first trannie (I was only little at the time). Let me know if you ever want to sell it.
Paul |
25th Nov 2006, 5:36 pm | #13 | |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
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Re: PYE 170BQ No LW
Quote:
Matty |
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26th Nov 2006, 6:09 pm | #14 |
Nonode
Join Date: Jun 2005
Location: Western Lake District, Cumbria (CA20) - UK
Posts: 2,136
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Re: PYE 170BQ No LW
Like all the Pyes of the period, a nice little set.
Considering that they were built to a price and not the "Rolls Royce" end of the market by any stretch of the imagination I think they do pretty well forty years on. A nice job and in lovely cosmetic condition! Regards,
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Brian |