Beogram 4000 record detection issue

[alf]

Hi All,

working on my BG4000 which does have record detection issues:

first the detector arm bulb dies not come on ?
It measures about 40 ohm and is getting 6.3V supply when ON is actuvated.

checking the collector voltage at 1TR14 I should see a max of 2.2V  – the max I see is

1.6V.
Both, 1TR14 and 1C9 have been tested off board as good ??

what am I missing here and why isn’t the bulb illuminated ??

help would greatly be appreciated ??

ALF

[spassmaker]

Hi Alf

As the bulb is measuring about 40 Ohm it should be OK.

Check 1 R 30 (15 OHM) and all tracing connections.

About Transistors which are measuring off board in a good state….

If I pull one of these little BC5XX Transistors out I always put a new one in, cost only 5 to 20 cent and you’re shure that the new one will work.

Had already a lot of them measuring good, but a HFE about 20 or 100, too low in that case.

Hope it will help a little bit.

Kind regards

Christian

[alf]

Hi Christian,

thanks for the input, very much appreciated.

R30 measured 14.9 ohm !

i revisited that detector bulb, definitely not lighting up, so I put a “replacement” that lit up straight away as expected when 6.3V are present.

However that “replacement” is not the correct bulb – my hope is Martin (Dillen) can supply a correct one ?!

ALF

[hcraig244]

Alf

Does the record detection circuit work with the replacement bulb….or are there still issues?

Craig

[alf]

Hi Craig,

it worked before the original bulb went dead.

The “replacement bulb” has a different filament type – it lights up but does not produce

the correct light circle.p through the lense.

the correct bulb has been ordered from Beoparts shop yesterday – now its the waiting game until it arrives.

ALF

 

[Author]

Posts