Pye Black Box - Page 5 - UK Vintage Radio Repair and Restoration Discussion Forum

Rover2000 · 10th Dec 2013, 7:22 pm

I have a case for the BB/A that isn't perfect - someone else has already rubbed it down and vanished it. It looks very presentable and in better nick than the photos you include.
You are welcome to it for free, if you are anywhere near the M1 north London over the xmas/new year period.

kevinski · 10th Dec 2013, 7:47 pm

Thanks Rover2000 for the offer, unfortunately I'm up the other end of the country in Northumberland

Nickthedentist · 10th Dec 2013, 8:53 pm

That is quite rough!

Beware of "sanding" as you'll easily go through the veneer edges and make it look even worse. Best option is a cabinet scraper and/or chemical stripper.

I have to say that as your veneer is tatty, paying a courier to transport Rover2000's cabinet might save a lot of heartache, unless you like a real challenge.

Nick.

Good luck with it,

Nick.

kevinski · 10th Dec 2013, 9:35 pm

My idea is to chemically strip the top surface and give it a very gentle manual sanding and then to give it a few coats of varnish. Hopefully I'll find out what kind of veneer it is and find a few pieces to patch it out.

Kevin

suebutcher · 11th Dec 2013, 2:10 pm

Kevin, I've got a slightly earlier version of this player, and I think the finish is cellulose lacquer. It dissolves in acetone.

peter_sol · 11th Dec 2013, 3:45 pm

I notice that the record size detector lever is upside down.

kevinski · 11th Dec 2013, 5:42 pm

New stylus arrived today. Inserted into cartridge and put record on anticipating a pleasant half hour. Playing very quiet! I've not replaced the rectifier yet, could that be the cause or is it likely to be something else?

Kevin

suebutcher · 12th Dec 2013, 12:30 am

The cartridge could be faulty. Crystal catridges absorb moisture from the air over time, causing the element to expand and break. The result is low output, or no output at all. Another possibility is a faulty output transformer. Have you checked this yet?

matthewhouse · 13th Dec 2013, 12:18 am

What are the connections at the cartridge? You showed us the tag strip below but not the other end, just in case something is amiss there.

kevinski · 13th Dec 2013, 11:11 am

I'm getting 166vdc at the output transformer. Is this good?

Pictures of how the cartridge is wired up. (Please bear in mind these are temporary connections while try to find fault). I've also tried 3 different cartridges with the same problem so hopefully the cart should be OK.

suebutcher · 13th Dec 2013, 11:59 am

Should be 270V at the anodes of both EL42 valves, if yours is the Black Box Mark 2.

kevinski · 13th Dec 2013, 12:09 pm

It doesn't have EL42 valves. It has 2 x PCL83 and 1 x ECC82.

suebutcher · 14th Dec 2013, 7:12 am

Sorry, wrong model! So, according to the circuit you posted, the PCL83 output valves should each have 217vdc at their anode connections to the output transformer, and the high tension supply to the output transformer should be 220vdc. Perhaps there's a problem in your power supply?

kevinski · 14th Dec 2013, 11:23 am

Hi, Just done some measuring at the metal rectifier and I'm getting 212Vac going in but only 41Vdc coming out. This seems very small. Should I be getting more dc voltage?

Kevin

behindblueeyes · 14th Dec 2013, 11:49 am

Sounds like the rectifier is failing - definitely get it replaced with a bridge rectifier and a nice high-wattage resistor as described earlier in this thread. Compared to replacing some of the more awkwardly located caps this is an easy job.

kevinski · 14th Dec 2013, 12:03 pm

Rectifier ordered. Let's see if that cures the problem.

kevinski · 21st Dec 2013, 3:40 pm

New rectifier fitted with resistor and volume has increased a lot, still not as loud as I would expect though (I would say probably about a 4 or 5 on my everyday record player). Any ideas why or is the Black Box normally not very loud.

Thanks

Kevin

suebutcher · 22nd Dec 2013, 4:15 am

Mine's very loud, particularly playing 78s. I only turn the volume up halfway most of the time. I'm using a BSR TC8S crystal cartridge, and that's providing a good input to the amp.

kevinski · 22nd Dec 2013, 11:33 am

Some voltage readings from before I changed the rectifier and after.

Pin Valve 1 Valve 2 Valve 3
1 20/252 8/260 7/261
2 0/0 -1/0 -1/0
3 0 0 0
4 0 0 0
5 0 0 0
6 40/258 44/294 41/290
7 12/209 3/0 3/0
8 18/0 43/295 41/295
9 0 0 0

Do these measurements sound about right now?

Kevin

Herald1360 · 22nd Dec 2013, 1:25 pm

It looks like you need a bit more series resistance for your new rectifier.

See attached for what you should be aiming at:

(E is voltage, I is current)

10th Dec 2013, 7:22 pm	#81
Rover2000 Retired Dormant Member Join Date: Oct 2013 Location: Hemel Hempstead Posts: 24	Re: Pye Black Box I have a case for the BB/A that isn't perfect - someone else has already rubbed it down and vanished it. It looks very presentable and in better nick than the photos you include. You are welcome to it for free, if you are anywhere near the M1 north London over the xmas/new year period.

10th Dec 2013, 7:47 pm	#82
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box Thanks Rover2000 for the offer, unfortunately I'm up the other end of the country in Northumberland

10th Dec 2013, 8:53 pm	#83
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,844	Re: Pye Black Box That is quite rough! Beware of "sanding" as you'll easily go through the veneer edges and make it look even worse. Best option is a cabinet scraper and/or chemical stripper. I have to say that as your veneer is tatty, paying a courier to transport Rover2000's cabinet might save a lot of heartache, unless you like a real challenge. Nick. Good luck with it, Nick.

10th Dec 2013, 9:35 pm	#84
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box My idea is to chemically strip the top surface and give it a very gentle manual sanding and then to give it a few coats of varnish. Hopefully I'll find out what kind of veneer it is and find a few pieces to patch it out. Kevin

11th Dec 2013, 2:10 pm	#85
suebutcher Heptode Join Date: Jul 2012 Location: Daylesford, Victoria, Australia Posts: 675	Re: Pye Black Box Kevin, I've got a slightly earlier version of this player, and I think the finish is cellulose lacquer. It dissolves in acetone.

11th Dec 2013, 3:45 pm	#86
peter_sol Octode Join Date: Aug 2003 Location: Welwyn Garden City, Herts. UK. Posts: 1,906	Re: Pye Black Box I notice that the record size detector lever is upside down.

11th Dec 2013, 5:42 pm	#87
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box New stylus arrived today. Inserted into cartridge and put record on anticipating a pleasant half hour. Playing very quiet! I've not replaced the rectifier yet, could that be the cause or is it likely to be something else? Kevin

12th Dec 2013, 12:30 am	#88
suebutcher Heptode Join Date: Jul 2012 Location: Daylesford, Victoria, Australia Posts: 675	Re: Pye Black Box The cartridge could be faulty. Crystal catridges absorb moisture from the air over time, causing the element to expand and break. The result is low output, or no output at all. Another possibility is a faulty output transformer. Have you checked this yet?

13th Dec 2013, 12:18 am	#89
matthewhouse Octode Join Date: Jul 2006 Location: Willand, Devon, UK. Posts: 1,023	Re: Pye Black Box What are the connections at the cartridge? You showed us the tag strip below but not the other end, just in case something is amiss there.

13th Dec 2013, 11:11 am	#90
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box I'm getting 166vdc at the output transformer. Is this good? Pictures of how the cartridge is wired up. (Please bear in mind these are temporary connections while try to find fault). I've also tried 3 different cartridges with the same problem so hopefully the cart should be OK. Attached Thumbnails

13th Dec 2013, 11:59 am	#91
suebutcher Heptode Join Date: Jul 2012 Location: Daylesford, Victoria, Australia Posts: 675	Re: Pye Black Box Should be 270V at the anodes of both EL42 valves, if yours is the Black Box Mark 2.

13th Dec 2013, 12:09 pm	#92
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box It doesn't have EL42 valves. It has 2 x PCL83 and 1 x ECC82. Last edited by Mike Phelan; 14th Dec 2013 at 8:33 pm. Reason: Changed EEC to ECC.

14th Dec 2013, 7:12 am	#93
suebutcher Heptode Join Date: Jul 2012 Location: Daylesford, Victoria, Australia Posts: 675	Re: Pye Black Box Sorry, wrong model! So, according to the circuit you posted, the PCL83 output valves should each have 217vdc at their anode connections to the output transformer, and the high tension supply to the output transformer should be 220vdc. Perhaps there's a problem in your power supply? Last edited by suebutcher; 14th Dec 2013 at 7:21 am.

14th Dec 2013, 11:23 am	#94
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box Hi, Just done some measuring at the metal rectifier and I'm getting 212Vac going in but only 41Vdc coming out. This seems very small. Should I be getting more dc voltage? Kevin

14th Dec 2013, 11:49 am	#95
behindblueeyes Retired Dormant Member Join Date: May 2013 Location: Finchley, London, UK. Posts: 81	Re: Pye Black Box Sounds like the rectifier is failing - definitely get it replaced with a bridge rectifier and a nice high-wattage resistor as described earlier in this thread. Compared to replacing some of the more awkwardly located caps this is an easy job.

14th Dec 2013, 12:03 pm	#96
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box Rectifier ordered. Let's see if that cures the problem.

21st Dec 2013, 3:40 pm	#97
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box New rectifier fitted with resistor and volume has increased a lot, still not as loud as I would expect though (I would say probably about a 4 or 5 on my everyday record player). Any ideas why or is the Black Box normally not very loud. Thanks Kevin

22nd Dec 2013, 4:15 am	#98
suebutcher Heptode Join Date: Jul 2012 Location: Daylesford, Victoria, Australia Posts: 675	Re: Pye Black Box Mine's very loud, particularly playing 78s. I only turn the volume up halfway most of the time. I'm using a BSR TC8S crystal cartridge, and that's providing a good input to the amp.

22nd Dec 2013, 11:33 am	#99
kevinski Retired Dormant Member Join Date: Aug 2013 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 330	Re: Pye Black Box Some voltage readings from before I changed the rectifier and after. Pin Valve 1 Valve 2 Valve 3 1 20/252 8/260 7/261 2 0/0 -1/0 -1/0 3 0 0 0 4 0 0 0 5 0 0 0 6 40/258 44/294 41/290 7 12/209 3/0 3/0 8 18/0 43/295 41/295 9 0 0 0 Do these measurements sound about right now? Kevin

22nd Dec 2013, 1:25 pm	#100
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Pye Black Box It looks like you need a bit more series resistance for your new rectifier. See attached for what you should be aiming at: (E is voltage, I is current) Attached Thumbnails __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O