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[cam.in.head]

hi.a question to any car radio engineers please.i hope someone can help.
 i have a blaupunkt san diego dj head unit (radio,cassette).this is the type that has various other connotations such as milano rcr127,st malo rcm127,etc .fitted with the 8638308752 pcb from circa mid/late 90's. ? the one with the removable front,4x35w ,2 egg shaped 4 button controls to the left.
hope that has identified the unit !
i have a few of these in various cars and am having an issue with one of them.
radio crystal clear,remote cd changer perfect .all 4 amp channels perfect.
issue is with very distorted (gritty sounding) cassette  on both channels.    i have exchanged cassette decks from other unit. problem not on deck.
i have also swapped the 8 pin op amp in the top right corner of the board. voltage to this chip vcc is same on both units 8.54v.. also virtually all the electrolytics.  still the problem remains.

[LC0112G]

Do you have circuit diagrams for it?

During Covid Lockdown I did manage to repair a few Blaupunkt Memphis and CDP09 CD players, and managed to get the circuit diagrams for them. I can possibly dig them out and email them to you if it would help. Doubt they'll be exactly the same as the San Diego, but wouldn't surprise me if the chipsets were the same/similar.

The other option would be to talk to DaveDND down in Paington. Used to be a member here, but haven't seen him pop up for a while.

[cam.in.head]

yes i was wondering about maybee dave dnd.i think that is his trade ?
i dont have a schematic for mine and am struggling to find one.
its doing my head in at the moment !
i had 6 hours yesterday on it and today since 7 !
i know that part swapping isnt the ideal way but one board works perfect.

[LC0112G]

Ok, found the pdf, and it does cover the San Diego SQR48 - dunno if that's different to the DJ . Anyhow PM me your EMAIL address and I'll fire it over.

My guess at the gritty/distorted noise would be mechanical alignment between the tape heads and the tape itself (assuming everything else works Ok and it's not just a gritty pot)

[cam.in.head]

hi that would be great.
no its nothing to do with the deck as i have swapped it out .its a component issue somewhere.
il pm my email. thanks

[Doctor Gollum]

Long shot, but have you tried a different tape

[cam.in.head]

hi.
yes different almost everything !
fault is on one unit. deck (and tape ) plays fine in other unit.so its in the circuit after the pick up head amp and before the main power amp .changed the head amp and capacitors.

[cam.in.head]

after spending 2 full days on these im stumped. ive swopped every chip (bar one) and every capacitor between units. still unit 1 stays distorted.
i had another basic unit that came without the cd changer input so have swapped all the relevant components to make this work the changer and all seems good in that department.so theoretically im up and running but what a nightmare ! i was hoping someone who does ice for a living might have popped along and said something along the lines of ' oh its usually the ######### that causes that  but at least it kept me busy and gave me practise swapping chips !

[cam.in.head]

thanks for the diagram. similar in some places but not in others ! did point to the op amp but already changed that. maybee it got dameged in the swap so have ordred acouple more .
did message dave dnd but no response so maybee not on anymoreactively.