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
Do you hear the protection relay click when it does that?
It sounds like your Beomaster 1900 has more faults in the output amplifier section than just the power transistors that you found damaged. The blown -31VDC filter capacitor incident likely did more damage.
-sonavor
yes relays click if i do it with the caps off it stays out of standby
Okay, then you have some work cut out for you regarding finding the failed components. A big task I know but it has to be done.
interestingly i took it out of the case again connected everything back up and it turned on and stayed on!
just broken the power switch tho snapped a tab off
gonna try it back in the case
huge update
its working !
i just tried to set the idle voltage though and i dont seem to be able to get any results that make sensethe measurement is bouncing around all over the place it doesnt stay still an as soon as i touch the pot it changes even more
After you discovered that IC200 and IC300 were bad did you check TR214/314 and TR215/315 transistors? I would also check TR212/312 and TR213/313. I always change the R249/349 trimmers on my BM1900/2400 restorations. You didn't mention whether you did that.
I have replaced them Bourne's 3386p's
When I hooked up the speakers again the right Channel ID far quieter than the left it sounds ok just very quiet
Okay, but you shouldn't really operate it until you set the no-load current.When you were measuring across the emitter resistor for that no-load current adjustment did you make sure you were measuring DC voltage and not AC voltage?
it was fluctuating less than 1mV
im just taking it apart again to test those tr numbers you mentioned
i assume the TR's you mentioned are these ones
those are ok 212/212 213/313
Brokenstereo: it was fluctuating less than 1mV
So you adjust and measure about 12mV across the 0.47 emitter resistor on each channel?
Duplicate post
Yes or near as damn it I was surprised how sensitive the adjusting was, breathing near it and changed dramatically they were 250 ohm ones I replaced them with
I should say I think I measured the right resistors it was same as pics on beolover
I like to replace the idle-current trimmer resistors with the multi-turn style. They make much finer grained adjustments than the single-turn type.
i cant find any at a reasonable price in the uk
I like to use these.
It's silly it's £12 postage yet £5 for the parts
Do you think I could get away with a 200r or 500r version ? I can get them without stupid postage costs
I would stick with the 250 ohm single-turn trimmers you have. They are fine. I just like the multi-turn better but as you say, not for shipping costs that are more than the part. It is probably similar here but I always do orders with Mouser, Digikey or Newark when I have a lot of parts to order. So the shipping cost works out more reasonably that way.
does anyone know what this type of capacitor is ? its in my beogram 1600 type 5713
It's a styroflex type.One of the most reliable components on this planet.
Martin
doent need replacing then ?
once i had the beomaster "working" i tried the beogram and it was humming loudly so thought lets replace the caps . so this one shouldnt need replacing then?
the electrolytic caps ive id'd are 10uF 63v, 4.7uF 63v and a 470uF 40v
also
what do you think may be the reason the output from the right chanel is so quiet?
ive replaced ic200/201/300/301 both sets of resistors per channel the trimmers too
the balance control seems to work as in it fades from side to side (is there better checks to carry out)
while i sit here waiting patiently for my second set of 5600 caps to arrive
ps thankyou for your outstanding service by email so far :)
pps do you have a spare power switch for the 1900?
If you mean an audio hum through your audio system then none of the capacitors in the Beogram will have anything to do with that.The audio path through a Beogram turntable is almost direct from the phono cartridge to the pins of the DIN connector that fits onto an amplifier phono input.The phono signals go through a connector or two but that is it. No other electrical components.If you are hearing an audible hum in the signal then either your grounding wire from the phono cable to the chassis of the amplifier are not connected or you have a problem with the phono cartridge.-sonavor
Brokenstereo: what do you think may be the reason the output from the right channel is so quiet?
what do you think may be the reason the output from the right channel is so quiet?
Are you connecting your speakers to the speaker 1 jacks or the speaker 2 jacks?The reason I ask is because if you happened to be using the speaker 2 jacks the little switch for them could be dirty.Otherwise I would probably suspect the volume control LDR device in the Beomaster 1900.Occasionally they cause problems.
iirc it was on both and its a new switch
might need to get martin to post me out a set of the ldr components then :)
Ok new trimmers in 200ohm worked ok new 5600 caps are in too.
There is still and imbalance in the levels and there is something up with the earth on the phono input as if I just plug a din cable in and touch it it makes noise
But second to that the platter on the deck is wobbling and speeds all over the place will need to check on what I replaced in that too
Add a little more tension to the DIN socket contacts.
Without trying to sound stupid
How :)
Thanks for the second set of caps they arrived yesterday.
Any thoughts on the Channel imbalance? Would your ldr kit be worthwhile? Is it hard to to get the distances right as you have seen do far I'm a hamfisted halfwit :)
A small screwdrive or similar tool in behind the socket contacts, one by one, and pry them a little bit together to increase the contact pressure.This photo shows speaker sockets but the principle is the same:
Difficult to diagnose from a distance - but check with a scope and see, where the left and right signals begin to differ in amplitude.
Knew you would say a scope!
Any idea what sort of spec I need I was looking a week ago and have no idea
I can't stretch too far seeing as buying this amp in the first place wasnt planed expenditure so all this following stuff sure as hell wasn't!
Dont know if it's related but when playing something through the tape input but the unit set to phono I could hear the tape input quietly but certainly there
Tried closing down the contacts in the phono socket no change