Beomaster 6000 Typ 2251 tuning balance issue

7 replies
AL
Offline
alf
Bronze
Posted January 20, 2020 at 08:56 GMT
#2255427

Hi All,

finally took some time to check out a couple of issues on my BM6000:

first replaced the bulbs for the tuning balance indicators and verified the light intensity balance = ok 

checked the upper and lower tuning voltage = ok

so far so good, but I noticed those balance indicators never change while tuning  in a station ??

meaning something is not right ?!!

can someone give me a pointer where else to look for a possible culprit ??

the other question I am trying to figure out is:

how do I get the uP board (board #2) out without dismantling the volume assembly (pullies & string) ???

how else would I be able to get to the display modules for repair ???🙄

as always, thank you so much for your assistance 🙏

ALF

AL
Offline
alf
Bronze
Posted January 22, 2020 at 11:43 GMT
#2255428

No one ???

well, i wonder how crucial it is to replace the tuning balance bulbs with the Exact Specified (6V, 80mA) bulbs in order to achieve the working balance indicators ??

they are difficult to find - all I could find were 6V 60mA bulbs !

the tuning imbalance shows at 8IC2 pin 7 & 10 depending on frequency being either too low or too high.

that should also result in a voltage variation at 6IC1 & 2 ?! But it doesn't !

dies that make sense ??

ALF

S(
Offline
Sehrbug (archived2)
Bronze
Posted January 22, 2020 at 12:30 GMT
#2255429

Hi ALF, I had the same issue because the light bulbs I was using was 6v 1W. 

I replaced them with 

https://uk.farnell.com/cml-innovative-technologies/01143800/lamp-bi-pin-t1-6v-0-69w/dp/1139288?st=light%20bulb%206v

and all working perfectly now.

 

Vitaly

DI
Offline
Dillen
BronzeModeratorFounder
Posted January 22, 2020 at 15:04 GMT
#2255430

The lamps are critical (which is also why it won't work correctly with LEDs).
I stock the correct lamps for the tuning discriminators.
Also for the volume dial illumination (which are different from the tuning lamps).

Martin

AL
Offline
alf
Bronze
Posted January 23, 2020 at 04:19 GMT
#2255431

Thank you Martin and Vitaly, much appreciated.

I asked that last question as I remembered a similar issue on a BM2000 and its Stereo indicator bulb !!!

so, the suspicions were there.

I will replace the bulbs with the specified one as soon as they have larrived.

what remains is the question of

'how to take out board #2 without undoing the cord of the Vol Pot assembly ??'

the cord (string if you prefer) is attached to a metal pointer and and indicator foil. I can't imagine it should be detached from that ?!!

not much point in doing a "half recap job", isn't there ?!

regards

ALF

DI
Offline
Dillen
BronzeModeratorFounder
Posted January 23, 2020 at 06:51 GMT
#2255432

Normally you don't have to take out the display board.
You can access the solderside when the Beomaster is open, and you can access the component side by taking off the glass panel.

Martin

AL
Offline
alf
Bronze
Posted January 23, 2020 at 12:05 GMT
#2255433

Yes, just remembered you can take off the control panel, open the uP box where you get to the two caps 220u and 47u.

thanks Martin for the memory trigger 😁🤙

ALF

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