Blaupunkt Nizza 21200 capacitor? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

tedzed1 · 16th Jun 2010, 10:48 pm

Hello again,some progress has been made, replaced R701 1k resistor as it had burnt up at some stage, and when a length of wire is attached to pin7 of the ECH81, it receves faint stations on MW, SW, and longwave, but nothing on FM.

Steve_P · 16th Jun 2010, 11:02 pm

Good. Now that means that it's the antenna circuit, which has been mucked about with. So, the next thing to do is try and put this right.

There are some pictures here...

http://www.richardsradios.co.uk/blaupunkt.html

Blow them up and see if you can see where things go, and check the wiring below as well. Has anyone got one of these and can help, I wonder?

For VHF, try an external aerial - you may be lucky.

Cheers,

Steve P.

Herald1360 · 17th Jun 2010, 12:09 am

If trying the wire trick let smoke out, are you sure that the two wires were not connected? The trick is that two separate lengths of insulated wire are twisted together with the insulation still on, so that the copper becomes the plates of the capacitor and the insulation, the dielectric. As mentioned above, since the capacitor is shunting the input to the ECH81, it won't be 1nF; 1pF is far more plausible. Caps with nF values seem to be identified by a "T" after the significant figures.

In any case, if C701 was shorted, R701 could suffer- R701 is the HT feed to the anode of the ECH81 via the IFT primaries and it looks like some settings of the switches connect the grid of the ECH81 to deck

tedzed1 · 17th Jun 2010, 12:46 am

Hi, just been having a look, this is a strange one, will try to trace antenna circuit tomorrow, i was getting a bad hum on KW, and some at each end of the MW band, but diconnected the capacitor that i substituted for a 1000pf (C701) and the hum has stopped, but still getting reception with a short piece of wire on pin 7 of ECH81

Paul

tedzed1 · 17th Jun 2010, 12:51 am

Thanks Chris, i understand now what you mean, yes i did bridge the two points with a piece of wire. somehow i when i was soldering it, i thaught i was doing somthing wrong.

spot the newbie

Paul

Herald1360 · 17th Jun 2010, 12:55 pm

Hopefully no harm has come to the ECH81- the other possible path to chassis for R701 via C701 would be a grid -cathode flashover in the valve

tedzed1 · 17th Jun 2010, 1:11 pm

Hiya Chris, thankfully the ECH81 has survived,have just found a capacitor of the same type under the chasis on the switch panel, will try to measure it tonight.

Regards Paul

Steve_P · 17th Jun 2010, 1:34 pm

If it's picking up signals then it probably is OK. The next problem is that antenna coil and it's wiring. This is part of the antenna or aerial circuit and without this being right then you will get nowt.

Sort this out and then try it

Cheers.,

Steve P.

tedzed1 · 26th Jun 2010, 7:23 pm

Hello everyone, not felt like messing around for the last Few days due to ill health, (both my chrohn's and arthritis decided to flare up at the same time), so finally sat down to try again today.
feeling well refreshed, sat down and tried to work out the antenna circuit, how difficult can three wires be, tried various combinations with no success, so decided to check to swith contacts again, to see if i missed anything,
newbie mistake no 149 had been made, what i had seen as four tone buttons, were infact three, the first button being marked F.ANT, so no need to say what i called myself, so now we had LW, MW & SW working, but as yet no FM, this was quickly remidied by a replacment ECC85, so now working across all wavebands fine, (yes steve p, you were correct, it sounds a cracking set) the only problem is the tuning indicator, which is a EM87, i have not got a spare, but i have two surplus EM84's. can i substitute with one of these, without too many modifications?

Regards Paul.

P.S i did not need to replace C 701, the set works fine without it.

Steve_P · 26th Jun 2010, 7:35 pm

The EM84 has a greater voltage range. Otherwise, yes you can.

http://www.r-type.org/exhib/aad0128.htm

Cheers,

Steve P.

tedzed1 · 28th Jun 2010, 6:25 pm

Its finally working, and it sounds great,

THANKS EVERYONE, could not have managed it without your help,

Regards Paul.

16th Jun 2010, 10:48 pm	#21
tedzed1 Hexode Join Date: Dec 2009 Location: Tamworth, Staffordshire, UK. Posts: 320	Re: Blaupunkt Nizza 21200 capacitor? Hello again,some progress has been made, replaced R701 1k resistor as it had burnt up at some stage, and when a length of wire is attached to pin7 of the ECH81, it receves faint stations on MW, SW, and longwave, but nothing on FM. __________________ Cheers Paul.

16th Jun 2010, 11:02 pm	#22
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Blaupunkt Nizza 21200 capacitor? Good. Now that means that it's the antenna circuit, which has been mucked about with. So, the next thing to do is try and put this right. There are some pictures here... http://www.richardsradios.co.uk/blaupunkt.html Blow them up and see if you can see where things go, and check the wiring below as well. Has anyone got one of these and can help, I wonder? For VHF, try an external aerial - you may be lucky. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

17th Jun 2010, 12:09 am	#23
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Blaupunkt Nizza 21200 capacitor? If trying the wire trick let smoke out, are you sure that the two wires were not connected? The trick is that two separate lengths of insulated wire are twisted together with the insulation still on, so that the copper becomes the plates of the capacitor and the insulation, the dielectric. As mentioned above, since the capacitor is shunting the input to the ECH81, it won't be 1nF; 1pF is far more plausible. Caps with nF values seem to be identified by a "T" after the significant figures. In any case, if C701 was shorted, R701 could suffer- R701 is the HT feed to the anode of the ECH81 via the IFT primaries and it looks like some settings of the switches connect the grid of the ECH81 to deck __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

17th Jun 2010, 12:46 am	#24
tedzed1 Hexode Join Date: Dec 2009 Location: Tamworth, Staffordshire, UK. Posts: 320	Re: Blaupunkt Nizza 21200 capacitor? Hi, just been having a look, this is a strange one, will try to trace antenna circuit tomorrow, i was getting a bad hum on KW, and some at each end of the MW band, but diconnected the capacitor that i substituted for a 1000pf (C701) and the hum has stopped, but still getting reception with a short piece of wire on pin 7 of ECH81 Paul __________________ Cheers Paul.

17th Jun 2010, 12:51 am	#25
tedzed1 Hexode Join Date: Dec 2009 Location: Tamworth, Staffordshire, UK. Posts: 320	Re: Blaupunkt Nizza 21200 capacitor? Thanks Chris, i understand now what you mean, yes i did bridge the two points with a piece of wire. somehow i when i was soldering it, i thaught i was doing somthing wrong. spot the newbie Paul __________________ Cheers Paul.

17th Jun 2010, 12:55 pm	#26
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Blaupunkt Nizza 21200 capacitor? Hopefully no harm has come to the ECH81- the other possible path to chassis for R701 via C701 would be a grid -cathode flashover in the valve __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

17th Jun 2010, 1:11 pm	#27
tedzed1 Hexode Join Date: Dec 2009 Location: Tamworth, Staffordshire, UK. Posts: 320	Re: Blaupunkt Nizza 21200 capacitor? Hiya Chris, thankfully the ECH81 has survived,have just found a capacitor of the same type under the chasis on the switch panel, will try to measure it tonight. Regards Paul __________________ Cheers Paul.

17th Jun 2010, 1:34 pm	#28
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Blaupunkt Nizza 21200 capacitor? If it's picking up signals then it probably is OK. The next problem is that antenna coil and it's wiring. This is part of the antenna or aerial circuit and without this being right then you will get nowt. Sort this out and then try it Cheers., Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

26th Jun 2010, 7:23 pm	#29
tedzed1 Hexode Join Date: Dec 2009 Location: Tamworth, Staffordshire, UK. Posts: 320	Re: Blaupunkt Nizza 21200 capacitor? Hello everyone, not felt like messing around for the last Few days due to ill health, (both my chrohn's and arthritis decided to flare up at the same time), so finally sat down to try again today. feeling well refreshed, sat down and tried to work out the antenna circuit, how difficult can three wires be, tried various combinations with no success, so decided to check to swith contacts again, to see if i missed anything, newbie mistake no 149 had been made, what i had seen as four tone buttons, were infact three, the first button being marked F.ANT, so no need to say what i called myself, so now we had LW, MW & SW working, but as yet no FM, this was quickly remidied by a replacment ECC85, so now working across all wavebands fine, (yes steve p, you were correct, it sounds a cracking set) the only problem is the tuning indicator, which is a EM87, i have not got a spare, but i have two surplus EM84's. can i substitute with one of these, without too many modifications? Regards Paul. P.S i did not need to replace C 701, the set works fine without it. __________________ Cheers Paul.

26th Jun 2010, 7:35 pm	#30
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Blaupunkt Nizza 21200 capacitor? The EM84 has a greater voltage range. Otherwise, yes you can. http://www.r-type.org/exhib/aad0128.htm Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

28th Jun 2010, 6:25 pm	#31
tedzed1 Hexode Join Date: Dec 2009 Location: Tamworth, Staffordshire, UK. Posts: 320	Re: Blaupunkt Nizza 21200 capacitor? Its finally working, and it sounds great, THANKS EVERYONE, could not have managed it without your help, Regards Paul. __________________ Cheers Paul.