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Old 7th Apr 2021, 10:44 am   #3
1955APREN
Hexode
 
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Join Date: Nov 2010
Location: Market Drayton, Shropshire, UK.
Posts: 411
Default Re: Grundig A 7400 (CUC220)

Hi Andy
I Loved Cuc220 one of the best set's ever. The circuit diagram is
on Pauls list top right of start page it can be downloaded for 1;99.
There are different versions of the panel.s when working on a panel
cheek the No on the panel with the right circuit digram
common faults

1 T634 Bu208a S/c Cause R646 gone high
Might also damaged I/C TDA4600 if so make certain that
C626 is fully discharged b4 fitting new I/C
2 Frame faults
none linar C2762 1000uf, C2764 220uf,C2774 100uf,
C2768 100uf ,
3 Tuner/ If Causing drift flashing video
Remove tuner/If unit ( 2 screws on pc side)
Pull tuner away from pins ( carefully not to bend pins)
remove sides of tuner , resolder all earthing bars to pcb
and replace all small electro/ caps
4. Trippler unit failure
These are the faults I remember hope they may be of help to
I cannot see Battery that you mention possible not on my version
of circuit diagram . Could you give ref No
Kind regards
Derrick

Last edited by 1955APREN; 7th Apr 2021 at 10:48 am. Reason: typo mistake
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