BeoGram 4000 tone arm problem...

28 replies
GG
Offline
Gravity Graham
Bronze
Posted November 23, 2022 at 11:26 GMT
#1650946
Thanks Craig - I'll check out the diodes.
I've already ordered a batch of new transistors, but I like your thinking about switching the inboard and outboard transistors..!
Also, after your recommendation, I have just ordered an Atlas DCA pro - as an early Christmas present from my wife (she's the one who wanted it made operational again!)
I'll update this post as I progress...

Best Regards - Graham H.

Location: Cornwall, UK

Obtained HND in Electronics Engineering in 1982.
Retired in 2016, and am still 'tinkering'. Have had my Beogram 4000 and BeoMaster 1900-2 since 1984.
HC
Offline
hcraig244
Silver
Posted November 23, 2022 at 14:12 GMT
#1650953
Found this in a 2012 - 2022 archived post "justins BG4000"

Powered up and this is what transpired:

unit sat powered up with no actions
upon hitting Start the platter drive started up at 33rpm
the panel ilumination lamps came on
the 33rpm speed selector lamp cam on
However the transport drive motor didn't run, I could change the speed from 33rpm to 45rpm but no other functions responded. Time to look at the circuit diagrams...... 

This is what I found....the following components where shot:

 

1D11 Diode
1TR33
1TR31
1TR30
1TR32
 

All of the components on the opposite side of the motor tested good.



 
GG
Offline
Gravity Graham
Bronze
Posted November 25, 2022 at 10:16 GMT
Edited November 25, 2022 at 10:19 GMT
#1651005
OK Craig - I thought I'd responded 2 days ago... Gone missing...
(Edit - didn't realise it had moved onto another page..)
Update:
I have ordered an Atlas DCA Pro as advised (early Xmas pressie from Missus) <3
I've got a few other bits to sort out while I wait for new transistors to arrive.
Now I've had a couple of lamps blow... probably from the switching on and off...!!
(So not switching transistors until they are replaced..)
While I'm at it I'm cleaning all the contacts  with cleaner and a glass-fibre brush/burnisher.
Just wishing I had more workspace, so I could do some fault-finding on my Beomaster 1900.....!!
Regards
Graham H.

Location: Cornwall, UK

Obtained HND in Electronics Engineering in 1982.
Retired in 2016, and am still 'tinkering'. Have had my Beogram 4000 and BeoMaster 1900-2 since 1984.
GG
Offline
Gravity Graham
Bronze
Posted November 29, 2022 at 09:46 GMT
#1651115
Think I have it sorted now..
Changed out TR28 and TR31 - nothing changed.  Took out TR29 and TR30, and tested them with my new Atlas DCA semiconductor tester - to find that TR29 has a short. !!
Followed up by switching them, and lo-and-behold, the deck will return and switch off (after winding the slider towards the middle !) - and as expected, the tone-arm will not travel inwards..
Replacement transistors will hopefully arrive today, and I'll replace all 4 as a matter of course..
I don't suppose you know where I can get replacement 6v 30mA lamps for the 33/45 indicators ? I also need 2 replacement 12v 30mA lamps for the position indicator ?
Regards
Graham H.

Location: Cornwall, UK

Obtained HND in Electronics Engineering in 1982.
Retired in 2016, and am still 'tinkering'. Have had my Beogram 4000 and BeoMaster 1900-2 since 1984.
HC
Offline
hcraig244
Silver
Posted November 29, 2022 at 16:58 GMT
#1651143
Dillen (Martin) from this site is your man......he can supply the correct lamps for you, send him a line.

 
GG
Offline
Gravity Graham
Bronze
Posted December 2, 2022 at 07:40 GMT
#1651232
Thanks Craig - actually got the lamps from BeoParts (Denmark).
However, After changing out the transisistors - it all worked (At last !!) - THEN..
I reassembled the deck and nothing worked !!
Not sure how - but TR29 & TR30 have packed in...
So - before I replace them again - I'll check all the diodes.
Graham H.

Location: Cornwall, UK

Obtained HND in Electronics Engineering in 1982.
Retired in 2016, and am still 'tinkering'. Have had my Beogram 4000 and BeoMaster 1900-2 since 1984.
GG
Offline
Gravity Graham
Bronze
Posted December 18, 2022 at 09:16 GMT
#1651575
Update: on 29th of Nov, I ordered 4 new BC144's on eBay (from Italy) - He sent them tracked on 2nd Dec, they arrived in UK on 5th... Still not been delivered.  I also ordered some electrolytics for my 1900 BeoMaster, from BEOPARTS in Denmark, arrived in UK on 6th Dec - Still sat in the Royal Mail distribution centre...

A friend in the Isle of Man, sent a package by Special Delivery on 5th Dec it finally arrived on the16th !  But, a package he sent by 2nd class mail on the 8th _ arrived here in Cornwall on the 9th !!

Location: Cornwall, UK

Obtained HND in Electronics Engineering in 1982.
Retired in 2016, and am still 'tinkering'. Have had my Beogram 4000 and BeoMaster 1900-2 since 1984.
GG
Offline
Gravity Graham
Bronze
Posted February 27, 2023 at 14:59 GMT
#1654136
I've finally given up on the BeoGram4000...  The BC144s never arrived, but did manage to source some from elsewhere.. After a while, I checked the voltage regulator cct - and found that it had blown, which is why I was taking out so many motor control transistors !   Replaced the voltage regulator, and all seemed to finally working correctly !  5 mins later everything blew again... Time to shelve it... Now concentrating on my BeoGram 6000, which has a tracking problem, but otherwise is good..

Location: Cornwall, UK

Obtained HND in Electronics Engineering in 1982.
Retired in 2016, and am still 'tinkering'. Have had my Beogram 4000 and BeoMaster 1900-2 since 1984.
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