ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
greetings all,
I am in the middle of trying to revive one of my old 4002 tables.
apart from the broken shutter/servo globe that I am still chasing,
the table won't spin when '33' is activated ?
it starts and spins perfectly when 'On' is activated - speed change switching between '33' and '45' does also work fine!
FYI: at the moment there is no shutter globe fitted, which should have no bearings I presume ?!
as with this model, almost every connection between moduls is hard-wired, no plugs :-((
looking at the lay-out of the keyboard and what is actually happening when '33' is depressed, I would follow the violet wire to the main board ending near ( 1C1, 1D2, 1TR1) and or 1TR8.
are one of these components likely to cause that problem or am I far off the track ??
any assistance is greatly appreciated - as always :-))
cheers, ALF
ANYONE ??????
Going to replace most of the metal-tin transistors as a first step !
ALF
Is that the record cleaning function, that doesn't work ?
Martin
yes Martin,
Precisely the problem - some of the 'tin-transistors' seem suspicious when checked ?!?!
Some other problems have emerged:
There seems a discrepancy between the circuit diagram and actual fitted components:
Fitted 4R4 = 8.2 ohm, circuit diagram 4R4 = 82 ohm ??
When 'ON' is activated the arm moves accross but as soon as it lowers the carriage
Races halfway towards the spindel, the arm lifts and the carriage moves back to its resting position ?
I tried to adjust the diaphragm without any success.
All this happened after replacing all old electrolytic capacitors !
Can anyone help ???
Thank you - ALF
Oops, correction
Circuit diagram is correct - I identified the wrong resistor !
Keep working on it, but it looks like
4R4 = 60 ohm, specified as 82 ohm - a pain to get acess to !!
4R1 = 9.6 ohm, specified as 8.2 ohm, 1 watt
Any further inputs ?????
Cheers, ALF
ok,
for those who are interested - here is an update:
I changed all electrolytic caps with either WIMA or Panasonic 105C caps on board 1 and 8 - done !
the eratic behaviour of the carriage/servo was caused be the hidden and missing spring of one of the lid bolts.
it went missing until I had to change 4R4 on board 4, lifted the board...and there it was :-)
further I managed to replace the burnt-out bulb in the shutter box with a 24V 40mA one - so far it works fine.
records play well again at this point in time and what is left to do is changing those tin-transistors and
hopefully restore the record-cleaning function - wouldn't that be nice ?!
I will keep you up-dated - thanks to all who are interested in that revival project.
Good work and we like pics
Collecting Vintage B&O is not a hobby, its a lifestyle.
Well done, you did the trick, by the way It will be interesting to know how did you manage to change the bulb in the shutter box, as all we know the little black retain bulb piece looks like not so easy to perform...
Ok,
After purchasing a couple of 24V/40mA wire-ended mini bulbs the first job was to extent their wires - lovely !!
The original bulb-fitting was a squarish plastic piece with the two wires sticking out.
This fitting bit with a tiny nipple fitted into a small black plastic mould, sliding onto the shutter cover.
After breaking off the head of the original bulb, I used that fitting bit to pin-down the two
Wires of the new bulb, holding it nicely in the center under the shutter cover.
Both extented wires were soldered into position - game over :-)
As there is no additional trimmer-pot to fine-adjust the servo it was quite tricky
To work out the diaphragm's correct height........
Sorry for the missing pics.........