General Forum

Re: Beogram 6000 and MMC 6000

Dillen — Tue, 03 Aug 2010 00:19:54 GMT

You must have shorted to something else since the two points you
show are connected to the same track.

If it ain't broken - don't try to fix it.
I agree, that a bit of electronic fault finding is needed now.

Martin

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Mon, 02 Aug 2010 16:49:19 GMT

I am so stupid. I should have left it alone while it's good enough. But I was picky. I tried to align the distance between turntable and the arms. The manual specified 23mm but I had either 22 or 24mm. So I followed the instructions to raise/lower the spindle nut. Then I thought some of the leads sticking out from the PCB might touch the under side of the inner-platter. The stupidest thing I did was using a clip to trim the leads short (and I thought I was smart enough to make sure I kept every trimmed bit out one by one) but I forgot to unplug the power cord.

When I clipped the lead A of 1R1, I shorted it with the adjacent lead B - and that set off a spark. I quickly unplugged and did something more stupid. I set the turntable in and plugged in again, then pressed START. The arms moved but the tonearm was already lowered. And it could not be returned to STOP position. Then I smelled something burning. I stopped and unplugged. The solenoid C (similar to the one that Graham successfully rewound some years ago) was overheated and the tape melted. Other than the tape, the solenoid looks fine to me.

Just checked. Looks like my coil is not fried. Hopefully the repair bill will be manageable. I hope it's just the resistors/caps that control the supply current. The resister that I shorted now measures 1.95 Kohm, compared to repair manual's rating 2.2 Kohm (10%), it should be still good. Must be some other parts along the circuit that's got fried.

Can't believe I'm so stupid.

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Sat, 31 Jul 2010 21:56:33 GMT

joeyboygolf:

Pin 2 is always the earth/shield connection

pins 3 and 5 are left and right and I assume pins 1 and 4 are the other two channels once decoded.

Hi Graham,

I ordered the DIN-to-RCA cable from Sounds Heavenly but Steve is going on vacation and won't be back in 10 days. I couldn't wait to try my Quadraphonic LPs. So I converted an old record/playback DIN-to-RCA cables from Philips, changing the male DIN plug to female DIN plug. Now I can confirm the pin designations for 4-channel Beogram 6000 as follows: Pin 1: Rear L / Pin 4: Rear R / Pin 2: Ground / Pin 5: Front R / Pin 3: Front L

I have three 5-channel systems in use (two of them tube amps) so hooking up with the Beogram 6000 is a breeze. I'm thrilled to report that everything on the Beogram works perfectly: from the vectored and helical modulations capabilities of the MMC 6000 cartridge to the SQ decoder circuit, from the stereo/CD switch to 4-channel output. I've been a multi-channel SACD and music-only Blu-ray advocate for years. Now for the first time, I hear something just as amazing in terms of concert hall presence - except the technology was more than 30 years old. Just think about that!.

Two other things I need to do with the Beogram 6000: re-adjusting the platter level and lubricating the arm dropping mechanism as Medogsfat suggested.

Again, thanks everyone for their valuable input! It's been a magnificent journey!

Cheers!

Re: Beogram 6000 and MMC 6000

tournedos — Wed, 28 Jul 2010 01:37:55 GMT

You should be a surgeon David

Good work, enjoy the Beogram

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Tue, 27 Jul 2010 18:48:16 GMT

Guess what, I fixed it! By just "replacing" the lamp.

I played two sides of an LP from start to finish uninterrupted and there's wasn't one hiccup. I tried all the start/stop/forward/backward/down/up control and it's silky smooth. The funny scratching noise was not present anymore anywhere. I only tried 2-channel and will report on 4-channel when I get the DIN-to-RCA 4-ch adapter.

Thanks for all the sound advice from all of you at Beoworld who responded in this forum. Most appreciated!

And a big thank you to you Martin - you said "without light from the lamp, you cannot trust the rest." You're exactly right.

However, the two thin wires of the bulb are too short and cannot reach the circuit board. There's no way I can solder anywhere. What I did was keeping the dead bulb by bending it up, placing the good bulb under it, threading the wires through the black plastic housing so that the new and old wires were held together in position. Then I used needle and thread to tie the wires together near the circuit board. I had the thread wound around the wires about 8 times and tied a tight knot every time - securing good contact of the wires and providing insulation so that the wires won't touch the inside of the aluminum arm.

I guess my needle work is better than my solder work

David

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Tue, 06 Jul 2010 16:04:41 GMT

Thank you Medogsfat! The eBay seller said that the item had a complete evaluation/tuneup and was fully operational before shipping. But I will definitely check the lubrication points you've detailed. I feel pampered with all the help from all ye wonderful Beoworld gurus.

David

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Tue, 06 Jul 2010 15:41:43 GMT

Thanks Mika! That explains the strange numbering of the pins. I've noted down your instructions for testing the arm. Looks like I'll have busy days ahead.

David

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Tue, 06 Jul 2010 15:34:49 GMT

Hey Graham,

So happy to hear you officially joining the rescue squad! (You've been guiding me all along since I started bidding for the Beogram 6000.) This Beolink info is really useful. Thanks! What I learned from this is that if you want the best, you have to buy from the real pros. You know what I mean.

Take care!

David

Re: Beogram 6000 and MMC 6000

Medogsfat — Tue, 06 Jul 2010 13:30:55 GMT

Lubrication points on the tonearm drop mechanism. You will need to clean off any dried residual grease & gunge before lubricating - they can be pretty solidly stuck & take a bit of application to get then apart, use sewing machine oil or silicon based lubricants. WD40 & similar products are OK to use only for freeing off the parts but NOT as a long term solution as they are acidic & won't do you any favours in the long run.

Re: Beogram 6000 and MMC 6000

tournedos — Tue, 06 Jul 2010 13:24:18 GMT

Where ever there is discrepancy, believe Dillen instead of me

Start with the lamp then. The click at the speed change is the speed control relay, it should be unrelated to this problem. I was thinking that if you try to cue the arm, hear a click but nothing happens, it might be the mechanical problem, otherwise probably electronic.

My BG6000 will lower the arm outside the platter when done manually. Start the deck, stop the movement of the arm immediately with either < or > (drive the arm back to the right to clear the platter if needed), and see/listen what happens when you push 'V'. You apparently have the later version (since there is a speed control relay) and it might behave differently, though.

The middle pin (ground) in the DIN is indeed number 2, as you can see in the diagram Graham linked. The numbering is odd since it started with a three pin version, then two more pins were added in between, and two more at the ends of the arc (and still more in the middle).

Re: Beogram 6000 and MMC 6000

joeyboygolf — Tue, 06 Jul 2010 12:38:32 GMT

Hello David

Here is the wiring of a DIN plug with pin numbers!

http://beotech.beoworld.org/mclconn3.htm

Pins 6 and 7 are missing in the 5 pin version.

Pin 2 is always the earth/shield connection

pins 3 and 5 are left and right and I assume pins 1 and 4 are the other two channels once decoded.

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Tue, 06 Jul 2010 12:11:56 GMT

Thanks Tornedos for your detailed explanations. I'm not great with electronics but I have soldered a tube amp kit not too long ago. I can follow instructions but I cannot diagnose problems.

I do hear a click when the arm comes to the threshold between 33 rpm LP and 45 rpm SP and the speed adjust dial switches over automatically. There's some scratchy noise (not sure where from) when the arm stays within the 45 rpm territory. You mentioned 5-pin DIN with the middle pin being ground and pins 3 and 5 are L & R front. Did you mean pins 2 and 5? I suppose pin 3 is the middle pin.

Oh no, I will never cut the original cord! And thanks for prepping me for 4ch reality!

David

Re: Beogram 6000 and MMC 6000

Dillen — Tue, 06 Jul 2010 12:10:44 GMT

David,

The little metal tongue is a grounding bronze leaf spring.
It makes a grounding (shielding) connection from the Beograms metal chassis
to the metal housing of the cartridge to prevent hum. Without it, the unshielded coils inside the
cartridge would act as antennas, picking up the frequency of the mains voltage etc. and it would
be amplified and come out the speakers as audible hum.

The tongue should have a little "contact bend" near its outer end.
It will normally point slightly downwards, almost parallel to the flat cartridge socket that sits above it
so it can enter the hole at the rear of the cartridge.
Bend the bronze leaf spring gently back down and test-fit the cartridge.
Do it little by little, you will easily see and feel when it is correct.

Martin

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Tue, 06 Jul 2010 11:57:59 GMT

Thanks Peter for your valuable input. Should the metal tongue be sticking out straight and fully inserted into the cartridge. At the moment it's folded and pushed flat onto the tip of the pickup arm and not threading into the cartridge. What is the function of the metal tongue and does it conduct any electronic signals?

David

Re: Beogram 6000 and MMC 6000

Beoreaucrat — Tue, 06 Jul 2010 11:51:17 GMT

My sincere thanks to Peter, Tornedos (Mika) and Dillen (Martin) for your most valuable advice. Yes, Martin, I shall start with the bulb first and then cross the other bridges later. I have your email address from our mutual friend Graham and we'll be in touch.

David