Hi and nice to meet you all!.

First of all I would like to thank Andreas for the support in setting up the account.

I've recently got a defective SABA 9141, with only known thing that is had a blown fuse.
With schematic diagram from internet, I've started the debug.

First of all, nothing happened upon power up (Fuse Si651 was blown with wire improvised - stupid DIY....
Upon further inspection, C231 was found defective and replaced. ST6 ribbon cable partially ripped (bad handling for sure). Rewired and soldered.

Power button pressed - no LED light.
FM pressed (or other mode selected) - Unit starts (radio can be heard on Headphones and 1 & 2 ports but in MONO. I'll debug this later...
Left LED's on but buttons to change values not working (not changing values).
Aus/off button (second from left) not working - can be turned off only with on/off button.

[attach = 6415] [/ attach]
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I've removed the power module, power supply module, IR module, relay module and checked the main areas. Also C2218 and C2217 are in parameters - actually all measures showed values ​​2-5% more than marked on components (measure off the circuit with a Fluke 179).

​Power supply signals were measured as indicated and seem fine(except K1 !?!):

​​H4 - 45.9V
H5 - 15.1V
K1 - 11.6V ?!?!?!
J1 - 19.9V

Trying to measure further the unit, it shut of by itself. I've restarted the unit and surprise - I was working (LED for STDBY and IR blinking when parameters were changed).
20-30 minutes of testing, multiple restarts and it was working....

I've stoped the unit, unplugged power cord, mounted the front panel (with some handling in headphones jack area) and restarted the unit - not workin anymore (same as first time - only partial).

Remeasured the main caps, resistors, diodes and no abnormality. I've found that STDBY LED even if off, when power off but in STDBY mode, it has 18V on it's terminals (measured to ground). Same on IR LED. if started with FM button, the value drops at 0.7V and when volumes or tone, bass, balance buttons are pressed the voltage rises at 16-17V. I don't know if this was also present at first - didn't measure.

I've resoldered any pads that were suspect, but no significant change.
The only positive thing is that now the volume and tone/balance keys work, but LED's change very slowly - 3-4seconds to move from one to another if "+" pressed, while "-" feedback is even slower (except volume - goes only up).
Upon restart, the units turns to sequence from the picture.

I've changed the IC632 with a 7818 but no obvious change.

I'm lost.... ? ( ? ( ​ ? ( ​
​
Any thoughts on where to look next?​​

Thanks,
Florin

Thanks for fast reply.

I've removed all the front left side boards and started to inspect them under magnifying glass.
With no obvious visual issues, I've started to check the continuity of the ground with a multimeter.

When measured, despite track on PCBA, there was no connectivity between the grounds pins of the jack board (the one with lots of diodes, bridging the power supply board and control indication board.

Upon further inspection, one track on PCB was found broken - most likely due to handling issues. I've removed mechanically the coating and solder bridged the area:



Plugged in all the modules and the unit is working perfect:



Currently I've added the top cover and I'm doing a burn in test (running for 8+hours):



Regarding the 11.5V, I've measured the resistor and it's 2.4ohms but if I'm measuring the Tester leads, I'm already having 0.2ohms from probes, so I guess it's in the right parameters (2.2ohms).
The next thing that is not working as it should, it's the stereo receiving - sounds fine (strong signal) near the green light. Stereo led is offset and the reception is very poor in that area. In fact, it's very "narrow" so stereo signal can't be acquired.

I've hooked up my Lenco L78 on the Phono and it sounds awesome - I'm playing some vinyl for few hours now.

Any thoughts regarding the stereo poor reception?

PS: all the SABA's have that many soldering flux residues? Mine looks like a full bucket was dropped on it. I've wasted half a flux-off can to clean only the areas that I've worked on.

On Phono the signal is processed in Stereo, therefore I suspect that only FM module has some problems.
I've seen that is quite complex to align it and I don't have the tools for it.

I'll just clean some contacts to see if there are improvement and I'll guess I can leave it as on the FM decode.

I must admit that I'm quite surprise by the quality on the Phono input - preamp is better than my Pioneer A550R. Sound is more profound (same speakers used - Wharfdale).

I'll give it a shot these days and I'll let you now if I manage to improve something.

I've found that P901 was broken therefore I've replaced it.

Tried with a little jiggle (left - right) but no stereo signal on radio.

When tuning there are moments where stereo led turns green but in that portion the signal is bad (look like an offset).

When using another source, the signal is stereo so I think that the tuner itself has some problems.

Also P512 was broken.... replaced it and did the tuning in parallel with another Tuner that I have (ST-J75).

Picked a radio station on 89.2mhz and tuned the P512 to get best signal.
Picked a station at 107.3mhz and tuned the P516 for best signal.
With some fine jiggle of P901 and P911 and I have Stereo (with green light).



It sounds great!!!!

Thank you also for support.

It worked fine but there are moments when one speaker gets muted on radio - fiddling stereo board, sound turns back on both speakers. For sure I need to spend some time with the board under microscope to look for some cold solder joints or maybe broken ones.

PS: I've got my second SABA (8061 Telecommander) in reasonable good shape but it does require some attention . It was about 20eur so I couldn't leave it behind...

kugel-balu schrieb:

One speaker muted -- also on the second set of output ? I'd first check the relay, unless you changed that already. Most of them are corroded by now.

Cheers,

Michael

There is no click/relay noise - it just turns off.
Slightly pressing the stereo board and the speaker is back on.

I'll give it a try on all sources to see if it's related to FM mode or to all modes.

I've inspected the FM board and found 2 solder joints cracked - re-welded and it works fine on radio.



Occasionally, one channel stops - no audio, but background noise. Happening on Tape 1 and 2... I'm using it every day so I'll keep an eye on it to look for any misbehaviors.