Decca compact 3 sound system. - UK Vintage Radio Repair and Restoration Discussion Forum

nickB45 · 15th Sep 2020, 9:42 pm

Hi new here have just obtained a Decca Compact 3 can anybody suggest where I can find a circuit diagram, works on only the left channel have replaced fuses swapped speakers around any suggests as limited technical in depth knowledge.

kirstyd · 15th Sep 2020, 10:22 pm

Is it just the recordplayer that only works on one channel or the radio as well? If so it could be the cartridge.

nickB45 · 16th Sep 2020, 11:49 am

Hi both turntable and radio section thanks

Edward Huggins · 16th Sep 2020, 12:08 pm

Try cleaning the input selectors with a contact cleaner spray - Servisol 10. If this doesnt work, it may be a component/s or power suppy failure in the RH channel. How good are you at circuit tracing, trouble-shooting, voltage measuring and soldering?

nickB45 · 16th Sep 2020, 1:08 pm

Have cleaned rotary and push button controls with switch cleaner, reasonably proficient with soldering, can trace voltages with basic multi meter, have been unable to find any circuit diagram on the internet.

AC/HL · 16th Sep 2020, 1:37 pm

Can you post a photo of the chassis. There have been a few threads about this unit, several say it uses Mullard audio modules, but one indicated that there was more than one version.

Robint 47 · 16th Sep 2020, 2:33 pm

There were 4 versions of the compact 3 The model no on the back an AT or DS followed by a four figure no will in define which model .The early ones use mullard modules in the output stage, followed by a complete change of output stage ,using MP8112 or MP 8113 output transistors. The final change was to TIP29 or TIP31 outputs. Preramp was always Decca design as the 551080.
Tuners were of Decca design the AM module remaing basic same design but Fm was changed mid production would need to see a photo to determine Decks were BSR units plenty of threads on site for this cartridge Acos GP 104 There is no service manual for any compact3 instead service sheets for each module.

Robin

nickB45 · 16th Sep 2020, 5:33 pm

Hi number on rear of unit is DS5226 appears to be using 4 number MP 8113, deck is a BSR which i have serviced and works well on the one channel no audio on the RH side from the radio or deck, will post photo tomorrow thanks.

nickB45 · 17th Sep 2020, 1:20 pm

Photo attached of the chassis for the Decca compact 3

Robint 47 · 19th Sep 2020, 2:47 pm

The 5226 audio is covered by the Decca 613 service sheet. I have a copy of this which i can scan and make available to you. pm me your address. Please note as this does not appear on the VRSD I am making a copy available to said site for future.
As you have checked speakers and fuses ok. Check continuity of din sockets then 630 ma fuses on main amp. If ok looking at leakage in transistors, but with power OFF easy to do a comparison from side to side.
It will take me a couple of days to scan and send circuits #

Regards Robin

nickB45 · 19th Sep 2020, 7:07 pm

Hi Robin thanks for your very kind offer my address is: Removed by moderator. Please use PM.

I have checked the fuses they are both OK I suspect the MP 8113 transistors could be the problem but have drawn a blank in trying to locate replacements, I will check the din sockets tomorrow.

Regards
Nick

nickB45 · 19th Sep 2020, 9:02 pm

Hi sorry new here what does pm refer to thanks

kirstyd · 19th Sep 2020, 9:05 pm

i had the same problem on a DECCA899 [the radiogram version of this set]. The problem was a bulging capacitor on amplifier. Simple to spot I know. Putting in a new one brought the thing back to life.

Simon Gittins · 19th Sep 2020, 9:07 pm

PM is Private Message, there's a link at the top of the page under your name.

nickB45 · 19th Sep 2020, 9:14 pm

Thanks for the help

Thanks have checked caps but only quickly will check again, regards

Robint 47 · 23rd Sep 2020, 2:10 pm

Nick can you please supply an email address not postal by pm.
If all fuses are intact it is unlikely output transistors you can use MP8112 as an alternate google for a supplier. In the event one or both faulty you would need to change both in the faulty channel.
Is there any sound from faulty speaker ie pops cackle hum etc. or any response when you touch inputs to amp or pre amp bear in mind mains voltage is present. With service data you can check components and compare on each channel this being done with mains off.

al_kaholik · 28th Sep 2020, 11:47 am

Sorry to jump in, were there differences in the SRG899 sets as per the compact sound 3 or were they a standard make up?

I have one and although I haven't got far in fault finding yet there is a loud hum from the left channel. This is present on all sources, and the audio board looks the same as that pictured.

15th Sep 2020, 9:42 pm	#1
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Decca compact 3 sound system. Hi new here have just obtained a Decca Compact 3 can anybody suggest where I can find a circuit diagram, works on only the left channel have replaced fuses swapped speakers around any suggests as limited technical in depth knowledge.

15th Sep 2020, 10:22 pm	#2
kirstyd Heptode Join Date: Mar 2014 Location: Leeds, West Yorkshire, UK. Posts: 902	Re: Decca compact 3 sound system. Is it just the recordplayer that only works on one channel or the radio as well? If so it could be the cartridge.

16th Sep 2020, 11:49 am	#3
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Re: Decca compact 3 sound system. Hi both turntable and radio section thanks

16th Sep 2020, 12:08 pm	#4
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,326	Re: Decca compact 3 sound system. Try cleaning the input selectors with a contact cleaner spray - Servisol 10. If this doesnt work, it may be a component/s or power suppy failure in the RH channel. How good are you at circuit tracing, trouble-shooting, voltage measuring and soldering? __________________ Edward.

16th Sep 2020, 1:08 pm	#5
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Re: Decca compact 3 sound system. Have cleaned rotary and push button controls with switch cleaner, reasonably proficient with soldering, can trace voltages with basic multi meter, have been unable to find any circuit diagram on the internet.

16th Sep 2020, 1:37 pm	#6
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Decca compact 3 sound system. Can you post a photo of the chassis. There have been a few threads about this unit, several say it uses Mullard audio modules, but one indicated that there was more than one version.

16th Sep 2020, 2:33 pm	#7
Robint 47 Tetrode Join Date: May 2014 Location: Bridgnorth, Shropshire, UK. Posts: 51	Re: Decca compact 3 sound system. There were 4 versions of the compact 3 The model no on the back an AT or DS followed by a four figure no will in define which model .The early ones use mullard modules in the output stage, followed by a complete change of output stage ,using MP8112 or MP 8113 output transistors. The final change was to TIP29 or TIP31 outputs. Preramp was always Decca design as the 551080. Tuners were of Decca design the AM module remaing basic same design but Fm was changed mid production would need to see a photo to determine Decks were BSR units plenty of threads on site for this cartridge Acos GP 104 There is no service manual for any compact3 instead service sheets for each module. Robin

16th Sep 2020, 5:33 pm	#8
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Re: Decca compact 3 sound system. Hi number on rear of unit is DS5226 appears to be using 4 number MP 8113, deck is a BSR which i have serviced and works well on the one channel no audio on the RH side from the radio or deck, will post photo tomorrow thanks.

17th Sep 2020, 1:20 pm	#9
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Re: Decca compact 3 sound system. Photo attached of the chassis for the Decca compact 3 Attached Thumbnails

19th Sep 2020, 2:47 pm	#10
Robint 47 Tetrode Join Date: May 2014 Location: Bridgnorth, Shropshire, UK. Posts: 51	Re: Decca compact 3 sound system. The 5226 audio is covered by the Decca 613 service sheet. I have a copy of this which i can scan and make available to you. pm me your address. Please note as this does not appear on the VRSD I am making a copy available to said site for future. As you have checked speakers and fuses ok. Check continuity of din sockets then 630 ma fuses on main amp. If ok looking at leakage in transistors, but with power OFF easy to do a comparison from side to side. It will take me a couple of days to scan and send circuits # Regards Robin

19th Sep 2020, 7:07 pm	#11
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Re: Decca compact 3 sound system. Hi Robin thanks for your very kind offer my address is: Removed by moderator. Please use PM. I have checked the fuses they are both OK I suspect the MP 8113 transistors could be the problem but have drawn a blank in trying to locate replacements, I will check the din sockets tomorrow. Regards Nick

19th Sep 2020, 9:02 pm	#12
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Re: Decca compact 3 sound system. Hi sorry new here what does pm refer to thanks

19th Sep 2020, 9:05 pm	#13
kirstyd Heptode Join Date: Mar 2014 Location: Leeds, West Yorkshire, UK. Posts: 902	Re: Decca compact 3 sound system. i had the same problem on a DECCA899 [the radiogram version of this set]. The problem was a bulging capacitor on amplifier. Simple to spot I know. Putting in a new one brought the thing back to life.

19th Sep 2020, 9:07 pm	#14
Simon Gittins Heptode Join Date: Jan 2006 Location: Cornwall, UK. Posts: 506	Re: Decca compact 3 sound system. PM is Private Message, there's a link at the top of the page under your name.

19th Sep 2020, 9:14 pm	#15
nickB45 Diode Join Date: Jan 2019 Location: Highbridge, Somerset, UK. Posts: 8	Re: Decca compact 3 sound system. Thanks for the help Thanks have checked caps but only quickly will check again, regards

23rd Sep 2020, 2:10 pm	#16
Robint 47 Tetrode Join Date: May 2014 Location: Bridgnorth, Shropshire, UK. Posts: 51	Re: Decca compact 3 sound system. Nick can you please supply an email address not postal by pm. If all fuses are intact it is unlikely output transistors you can use MP8112 as an alternate google for a supplier. In the event one or both faulty you would need to change both in the faulty channel. Is there any sound from faulty speaker ie pops cackle hum etc. or any response when you touch inputs to amp or pre amp bear in mind mains voltage is present. With service data you can check components and compare on each channel this being done with mains off.

28th Sep 2020, 11:47 am	#17
al_kaholik Triode Join Date: Sep 2020 Location: Winchester, Hampshire, UK. Posts: 37	Re: Decca compact 3 sound system. Sorry to jump in, were there differences in the SRG899 sets as per the compact sound 3 or were they a standard make up? I have one and although I haven't got far in fault finding yet there is a loud hum from the left channel. This is present on all sources, and the audio board looks the same as that pictured.