Saba 9140: Mittenanzeige schlägt nach rechts aus

BAP 812 is a 6 V 2-2.3V stabilization diode.
If you replace it with a 6 V 2-2,3 V zener diode watch out, that zener diode has to be used with reversed polarity compared to the BAP812.

Type/manufacturer was Unitra/Poland. Extremely unlikely that you found it in a German Radio, probably Polish.




The data shown tell you that you can be easily mislead when measuring the diode with a diode tester because it has quite unusual U_F = 2 V.

Reinhard

Reinhard, are you sure re 6 V ? I find several possible values, it might be that BAP 812 is just the series, and the voltage is specified separately ? At least what I see in a search is somewhat confusing ...

Actually, doesn't the sheet say it is between 2,0 and 2,3 V ? And 6 V max. operating voltage ? More like an early version of a reference diode ?

Michael

Corrected!

Thanks Michael!

Maybe the radio was made in DDR/GDR with a few parts from Poland.

Andreas

A picture of the radio would tell ...

Thank you for your advice. I'm adjusting... ...

radiomuseum.org/r/hgs_tramp_we_100we10.html

Radio receiver Tramp WE-100 (world receiver) made in Poland by Eltra
(Unitra Eltra) factory in Bydgoszcz city. It was mono-version of
receiver Julia-stereo
(see in RMorg). Eltra was making the "Julia-stereo" in 80's - for
polish market in stereo-version only. Probably the model Tramp was
exported only to Germany (maybe to France and Austria too).
"Julia-stereo" was the best and the biggest polish portable receiver.

For the SW ranges, the receiver acts as a double conversion unit where 2 MHz is the 1st IF.

Thank you for your advice, thank you!

Dear teachers,

I bought a saba 9140 in ebay Germany and it arrived today. Unfortunately, it is missing a large knob and switch cap. Please ask teachers who have this knob+switch cap to transfer it to me and I will pay.

thank you.

Hello oldiefan, kugel-balu，

I have solved the problem of abnormal power supply and amplifier circuit of this 9140. Now I can start up normally and receive FM broadcast,

The problems are as follows: 1. FM 98-108 can receive sound normally, and the sound is good; 88-98 radio stations are vague, or there are almost no radio stations. How can I solve this problem?

2. I have replaced the small electrolytic capacitor.

thank you.

I report my work to the teacher:

1. All small electrolytic capacitors were replaced,

2. Replace all variable resistors,

3. All welding points on the circuit board shall be reinforced and welded again,

4. Check and adjust the voltage of all lines according to the circuit diagram,

The current status is normal, the sound is very good, and the sensitivity is high,

Only one problem has not been solved: FM/88-91MHz cannot receive radio stations. I don't know where to adjust. Please give me some suggestions.

Thank you.

wyx12007cba schrieb:

FM/88-91MHz cannot receive radio stations. I don't know where to adjust. Please give me some suggestions.

Please measure the tuning voltage when the dial pointer is on 88 MHz and when it is on 104 MHz. Measurement Point A5. The voltage readings shall be 3 V and 22 V DC.

Regards
Reinhard

Please measure the tuning voltage when the dial pointer is on 88 MHz and when it is on 104 MHz. Measurement Point A5. The voltage readings shall be 3 V and 22 V DC.

The measurement result of A5 point is:
when the dial pointer is at 88 MHz is 1.7v, 91.8MHz is 3.2v, and 108 MHz is 21.3v.

There are two trimmer-potentiometers (variable resistors) on the tuning voltage module (where also the integrated circuit TCA530 is located):
P512 and P516.


Adjust as follows:
1. Turn the dial pointer to 88 MHz on the large tuning dial
2. Attach Voltmeter to Measurement Point A5 (versus chassis gnd)
3. Adjust with P512 the voltage at measurement point A5 to 3,0 V DC.
4. Turn the dial pointer to 104 MHz on the large tuning dial
5. Adjust with P516 the voltage at measurement point A5 to 22,0 V DV
6. Turn the dial pointer to 108 MHz on the large tuning dial
7. Measure the voltage at measurement point A5. It shall read approximately 27,0 V DC.

Measure the voltage at measurement point B8: Shall be 31 V.
Measure voltage at measurement pont B9: Shall be 4 V.

Best Regards
Reinhard

After I adjusted P512 and P516, the fault was removed, and 88-108 received the radio perfectly. Thank you for your advice!

Congratulations!

Reinhard