(ENGLISH) Saba MI-215 one channel broken.

dmkbox · 18. Februar 2010, 10:46

HI! Sorry, I will ask my question in English.
I have fun with Mi-215 during half year, but yesterday one channel (left) stay silent.
When I turn balance knob to left channel - I hear sound from right channel. If no signal, I hear warm tiny noise in broken left channel. If signal exist, only weak distortion from broken channel.
I open cover and inspect. I substitute POWER amps - no fun. I substitute drivers - no effect. I measure voltage from input to linear amp (10V on both channels).
I suspect that problem somewhere in MID-BASS-TREBLE circuit. But I cant find.
I have no oscillograph, only digital multimeter.
When I set to MONO sometimes sound good from both channels. Sometimes only right channel.
Any opinions?

nightbear · 18. Februar 2010, 11:20

Hi there,

did you check the loudspeaker relay? Those relays tend to have problems...
Sometimes it´s useful, to hit it slightly with the handle of a screwdriver to see if there´s a reaction. Or - replace it.

dmkbox · 18. Februar 2010, 11:45

I even disassemble it, clean and check with separate PSU. It work.

dmkbox · 18. Februar 2010, 19:25

Look like TDA1029 on commutation board is dead. Is it spare available now?

dmkbox · 19. Februar 2010, 16:45

Yes, it was TDA 1029 (Ic1538). Replacing this chip keep amp alive.
Also I replace relay with new. And found new power switch in local bargain.
Great!

dmkbox · 21. Februar 2010, 15:01

HI again. Is it available replacement for volume knob? There are tricky potentiometr with upper contact pair and long thin shaft. Ebay search got no luck.

Rillenohr · 21. Februar 2010, 16:45

The knobs on the cheaper MI 212 are the same. Non-working MI 212s can sometimes be found at eBay for a few bucks. In most cases looking for a 2nd Saba is the only way to get replacements.

dmkbox · 15. März 2010, 19:05

Another little cosmetic trouble. Lamp on volumemeter burn out. Which replacement I can use? BL1703 not available. Maybe LED?

dl2jas · 15. März 2010, 20:38

Take a photo of the lamp.

Voltage? Ampere/Watts?

Andreas, DL2JAS

dmkbox · 15. März 2010, 21:02

12v 2W as signed on shema. Small lamp with pair of wire from it.

dl2jas · 15. März 2010, 21:58

A photo would be helpful.

Sometimes I use lamps T5 as a sparepart, the socket is solderable.

Andreas, DL2JAS