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
Dear All,
I have come across a fine set comprising the BeoMaster 8000, the BeoCord 8000 and the BeoGram 8000.
One channel of the BeoMaster 8000 was completely blown to smithereens. I ended up re-soldering all prints, replacing all caps and upgraded to a grade higher TIP's on the powersection. Also some to92's were shot on the powersupply and driver pcb's. It is awaiting final assembly now ;-).
I first turned my attention to the BeoGram 8000. I ordered a TachoDisc from Martin and got a bucketload of great advice from him (extremely grateful). I recapped the prints, re-soldered and re-lubed. Also adjusted settings on SO switch, alignment of arms and stylus pressure.
There is some weirdness still going on. On pressing PLAY the tone arm sometimes does not reach the beginning of the record. When it does, it moves a halve of a mm inwards and touches the styles in groove. I hear music from the needle ;-) On some instances the click for lowering the styles is followed by another click after touching down on the record, followed by raising the tone arm again and staying put.
Is this a sensing issue of some sorts? Or is there some issue with tracking? On clicking and raising i can see the tone arm pulling to the right a bit. It is in parallel with the sensing arm so this must be ok then?
And a final question. The screw below the tone arm assembly to pre-tilt the tone arm, is it to be set so that the sensing arm and the tone arm are at the same height when in stop-mode?
A lot of questions at once. But i feel i am very close to a solution.
Thanks in advance,Ramon
The Netherlands
PS i posted here in order to releave Martin from my Niagara Falls of questions via PM.
Update:
I got it to play in the middle of a track. And it sounds as if the MMC20 CL is top notch. Very nice highs on the brass and violins. No distortion of any kind (audible and nasty that is ;-) )
I now really want it to work flawlessly!!
PS Here is video of the 5 second touchdown and raising of arm.
@ the start of the record the raising (and clicking) is just a second after touchdown.
Tone Arm raising after 5 seconds
The three Ir diodes are registering purple on my smart-phone camera. So counting the revolutions of the wormspindle should be working.
A strange features that I've found out about this deck, but I can't find any proof or literature about, is that if the tone arm is kept in the same position for a period of time (don't know how it is counted) the system shuts off. I mean ALL the system, even the beomaster. I thought at first it was related with a problem with the beomaster, but I was able to recreate the feature with a godspeed you black emperor record, which has a closed groove at the end of the B side (it turns infinitely in the same groove, so after a short period of time, everything shuts off)
I think it might be a protection for when a record is skipping and you don't know it. If the carriage has not moved for a predetermined period of time, the protection occurs... So it might get you to an adjustment of the photo sensor below the tone arm... i'm currently trying to find the perfect balance but it seems to be difficult to achieve. Could you're problem be related to that?
Guillaume
Hi Guillaume,
Thanks for taking an interest and replying.
Yesterday evening i was able to have it play for a whole A-side of a record. This morning it fell into itś old habits again. The first time i pressed play, the arm stopped a whole cm before the record's first groove. Second time it came closer.
I also noticed that on the intro groove - when forcing the tonearm to set down by manual cueing and pressing play again - the arm turns in the horizontal plane towards the sensing arm. And when it reaches a certain angle the clicking sound is heard and the arm is raised again. When i set the tonearm down in the middle of a 30 minute track, the tonearm stays down a bit longer, but eventually clicking sound + raising of the arm.
I think the solution must be found in assessing which triggers are there to have the coil activate to raise the tonearm.
I also find the service manual not very useful in this matter. The whole aperture photo adjusting i do not really understand. And also the terminology used is very ambiguous. Under vertical parallelism of tonearm the adjustment made is just the opposite: namely in the Horizontal plane.
I do really want this player to work: as the sound it produces when it is playing a record, is pretty darn good. (Hooked up to am Marantz PM-94 with it's excellent phono stage).
Regards,Ramon
Update and possible solution.
I took some measurements on pin 4 and 6 of P5. I never thought this to be the culprit. But Martin (Dillen) has posted some time ago that this adjustment might be more important for the entire functioning of the Beogram 8000 then the two buttons < << and >> > may imply ;-)
They were @ 1,2v!!!!!
I adjusted them down to 750mV. No further adjustment was possible or the screws would fall out of the thread. But the turntable now starts every-time @ the beginning of the record (with it's trademark 3 mm hop inwards), sets down the stylus and plays heavenly!!! Now it's is time for a DIY record cleaning machine, for which i have all VPI parts and vacuum laying around for years..
I have heard some turntables throughout the years, but this combo (i have the MMC20 CL) is rather extraordinary. Although the Marantz PM-94 may have something to do with it. It has some very unique transformers on it's phono board.
I will keep this post updated on the reassembling of the BeoMaster 8000.
Maybe it would be beneficial for some to create a Beogram 8000/8002 repair thread (sticky) in which all info on restoring these beautiful creatures is put in a 'howto'.
Playing some records, and loving it!
Nice work, Congrats!! I think I also may have solved my problem, but I might start a thread about it soon... just to have some opinions about it..