Pye Black Box

[Michael Maurice]

Have you tried a 3.5mm jack to two phono plug leads to connect the output from a MP3 player/computer to the amplifier.

It works for me though the volume is somewhat reduced.

[Sideband]

Originally Posted by kevinski

The two PCL83s glow a warm orange but the existing ECC82 is more like a dying ember.

This is NOT an indication of dud valves. Some valves have heaters that are more exposed than others and appear brighter.

The ECC82 may well be low emission but the brightness of the heater is not an indication.


Rich

[Ed_Dinning]

Hi Kevin, any similar size of push-pull output transformer would do for a trial.
The old dodge of using a 6.3 + 6.3 v mains transformer backwards would probably not work as this will have too high a ratio.

PM me if you want to ring and discuss.

Ed

[nigelr2000]

I am sure there was a way to test a winding using a scope and I Just found this, not sure if it would work for an audio tx but might be worth a look http://www.radios-tv.co.uk/?q=node/31

[Techman]

I confess to not having read all this thread (so I could be wrong and this has already been tried), but it does sound like a weak cartridge.

[kevinski]

I give up! All sound has now disappeared. I can not get anything from the cartridge, I've tried what I think is a different source ie mp3 player via headphones/phono leads etc. but all dead. I get quite a gentle hum from the speakers as the valves warm up but that's it. 7 pages in and it's worse now than when I started lol. (Anyone want to buy a Pye Black Box? Going cheap!!! Only joking(at the moment))

Kevin

[unitaudio]

Hello Kevin. You've had the patience of a saint. I'd have knocked it on the head ages ago! So fair play to you for sticking with it so far. However, sometimes these things just seem so keen on fighting you it seems pointless trying to stop them. I know this is easy for me to say but what you need to do now is walk away for a bit. It might be for a couple of days, weeks or even months.

My dad gave me that advice when I was a lot younger and faced with a similar situation. It worked for me.

This thread has been absolutely fascinating. It's been better than any soap opera! Then again, most things are better than any soap opera...Who needs a telly?! (Actually, this is probably just about the worst place to say that!)

Hang in there mate. In the fullness of time, it'll probably make sense. Eventually...

Regards
Paul

[Station X]

Don't give up now. All the forum members who gave you advice will be disappointed.

Apart from that, it's much easier to fix something that is completely dead than it is to fix something that works a bit.

[Michael Maurice]

Ed Dining has offered you some assistance, may I suggest you take him up on his offer.

[Nickthedentist]

Yes, by the time a thread has got to seven pages, if someone's offered to help, then go for it! Remember the "mcourtman saga", anyone?!

[kevinski]

Tried the deck through a different amp and it worked fine. Plenty of volume etc so at least I know that is ok. Moved unit while still plugged in and pilot light started to flicker on and off so there must be a loose connection or an intermittent short circuit. Will look again after work.

Kevin

[kevinski]

Panic over, a tag had come adrift off one of the tag strips hence no volume. Soldered it back and it's back to low volume!

PM'd Ed for advice.
Kevin

[kevinski]

Ed has very kindly offered to check over the output transformer so I'll take it over to his place during next week and see if it is that which is causing the problem. Meanwhile I think I'll tackle the deck and it's glue/lubricant.

Thanks

Kevin

[kevinski]

Just back from Ed's. The transformer seems to be pretty much OK so gawd knows what the problem is. Ed suggested trying a different deck so I'll give that a go tomorrow and see if that does anything.

Kevin

[behindblueeyes]

Well that's good news as the transformers are not easy to come by.

My only experience in this area is having brought one of these back to life through the kind assistance and some donated parts from forum members on here, plus trawling through countless repair threads on here.

As you've replaced most of the internal components I can only suggest the following which don't seem to have been discussed so far:

- Trying the speakers with a known-good amp to rule out a problem there (though be careful as there are 4 speakers wired in parallel so the impedence will be very low - I tested mine with an old Technics mini system).
- Could it be one of the tone controls or volume pots? I would start by shorting out the volume control to effectively bypass it.
- The valve bases can be a problem with Black Boxes. Spares are available, but can imagine they'd be a pig to replace as you'd have to drill out the rivets and disconnect a lot of components. If you are careful you might be able to use a sharp object to close the contacts a little, ensuring that they are firmly gripping the valves.

None of the above was a problem with mine - I 'only' had to replace the mains transformer, rectifier, all of the capacitors and resistors, the cartridge & stylus on the deck, and install 3 new valves.

Saw one of these on sale at a Brick Lane vintage market the other week for £400! More than twice what they go for on eBay, but proof that it's a desirable object once fixed up.

[Radio_Dave]

Hi Kevin,

In an earlier post you've mentioned that you've connected an mp3 player to it, without success.

It looks like your transformers are OK and that's good news. Apart from a few capacitors and resistors their isn't much else to this amplifier. With all due respect, I'm sure there's something really simple that you're missing. Check all the components and connections against the circuit diagram and see if you can find a mistake somewhere.

David

[kevinski]

Been back through everything and the only thing I could find that I was a bit unsure of was where the tonewires attached to the tag board. I moved the position of the green wire from tag above the red in pic to tag on the right of the red and the volume seems to have increased but now I have a problem with the deck (see new post if you dare!) Can anyone say whether this is the correct position or not.

Cheers Kevin

[Station X]

If I understand it correctly, moving the wire should have made no difference at all, since the two points mentioned are commoned together.

I assume that the "tonewires" are routed through the tone arm to the cartridge. If so how are they connected to the cartridge.

I have to say that so much insulation has been stripped from the green wire, that there's a risk of it short-circuiting to the common point previously mentioned.

[Station X]

I've just looked back at post 62 which shows the same tag strip. The wires there are both red, possibly screened and neatly terminated. Now it looks a right mess.

https://www.vintage-radio.net/forum/...3&postcount=62

Where did the green wire appear from and what happened to the other red wire?

[kevinski]

Station X please see post 66 and post 91

Kevin