Thanks for the information!

Yes that is what I was afraid of too, making parts units of my two working ones.   They are functioning at a high level and the little annoyances are not a huge deal to me right now.   

Good idea on the parts machine, I'll tinker around with it some.   I don't even have a good soldering iron so I won't be doing any of that anytime soon.

I do have many years experience fixing PCs and building them.   So I have a little handyman in me.

I pulled that mute relay/din socket part.   It had a metal shield over a yellow rectangle shaped part.    I was expecting some kind of mechanical switch. 

Also how do I pull that circuit board that is under the push buttons?  

-  It looks like it slides out from these plastic clips.   I am not sure if I take the top button plate off first of the board first.

- Also not sure how that black power box comes out.   I don't want to force anything.

You can see the control button plate open link. You do have to be gentle and careful with the removal but basically, you pop it open from the top then it slides off the bottom (front of the Beogram). The top part is held in place by plastic tabs. You can see one in the picture. The transformer pops off its connector by pushing it up from underneath the Beogram. When you look underneath you can see the rectangular base of the transformer (middle of the page ).

I did push that transformer box from underneath but could only get the far side to come up because the board is blocking me from pushing it up evenly on both sides.   And it looks like the transformer has to come out first in order to slide the board out from the thick plastic clips.

I was pushing on the outside edge of the lid from below but not directly on the power box.  I did not want to push on the transformer in case the lid was to come out first to unhook something.

So can I just push on the transform part and it and cover will just pop up?   I'm just cautious because its pretty tight fight and do not want to break that old plastic if I can help it.  I appreciate the guidance.

the front end of the transformer is where 12? heavy terminal pins grasp the main board; that is the area you need to push up on; I don't think anything else retains it. Other than the pins and the lid, I don't think anything else restrains it, but I could be wrong. I remember having to push fairly hard and on the terminal end of the unit to get it out.

I took a photo of the inside of the Mute relay.  Is that a seal unit, if its bad is it fixable? 

Login to view image

pfcs49 wrote:

the front end of the transformer is where 12? heavy terminal pins grasp the main board; that is the area you need to push up on; I don't think anything else retains it. Other than the pins and the lid, I don't think anything else restrains it, but I could be wrong. I remember having to push fairly hard and on the terminal end of the unit to get it out.

Right, there is a connector on the transformer that slides right onto the pins of the main circuit board. The whole transformer assembly slides up and out the top. It does fit fairly tight but if you keep applying pressure to the base with your thumbs it should start to move. After that, it is a little tricky getting the circuit board assembly out with the control panel attached but it can be done if you go slow and are careful.  Once out, I re-attach the transformer when I want to run some tests.

-sonavor

@sonavor-I hope you are a quick learner! You may need to learn some basic electrical stuff to be effective here.

That is the relay; all that I've opened had clear covers. If this is the turntable that develops a weak channel, you could try removing the cover (I coached you somewhere how to do this-AK?) and treating the contacts or perhaps slipping paper between them to see if the problem resolves.

One diagnostic possibility is to read and understand wiring diagrams, understand things like relays and resistance, and basic circuitry, understand Ohms law and it's implications; then to apply simple logic to see ways to diagnose problems like this one with a VOM (volt/ohm meter) Failing that, you really will need a "self-healing" Beoggram! or you will be in a real quagmire!

Thanks,  yes I am slowly doing a refresher on basic circuits.   Hands on is totally different than on paper.    Right now I am just trying to get it apart without breaking anything.    That photo is from my parts unit not the one with the weak channel.   

I don't think it was me you coached on AK, I was not even to the point of removing the cover.   But I can use it now.

I am not even close to soldering anything.  I am asking questions to get a better understanding of how it works.    I have no idea how that mute relay works right now.  Even If I knew exactly the problem I would not fix it yet.   I don't even own a decent soldering iron so I am light years behind you Obi Wan :)

I guess what I meant was are the parts in the little relay generic?   Lets say that little yellow box is bad, is that a replaceable part?   Or is this more about broken wire, bad solder or resistor (which are generic parts)  I think I only saw two resistors on that relay.

I appreciate the help.

there's scores of relays and many differences, but this one is very simple. One magnetic coil (with 2 terminals) pulls the 2 pair of relay contacts (one pair per channel) apart when un-muting, which separates the + & - signal circuits/wires  from their formerly joined/shorted/shunted muted state. 

But if the relay or associated circuitry is the fault, it is a tricky one! The circuit is relatively high impedance/resistance (the resistance of the cartridge) while everything else in it is very low resistance. To cause such a roughly halving of signal strength requires a fairly high resistance fault, and that is not likely. But if this is truly a fault between the DIN socket and the cartridge plug, and NOT the cartridge or the stuff downstream of the DIN socket, (interconnect and amplifier) then it is somewhere between those points. And if it is, an ohmmeter is your best friend! As I alluded to, you could remove the plastic....wait-I'm checking....yes, here is my response to you on AK:

#link      link 07-05-2014, 01:12 PM

pfcs49  Phil   Join Date: Dec 2007 Location: N/W NJ, USA Posts: 1,082

No. The muting relay is mounted on a small circuit board that is part of the DIN plug subassy. The relay is covered by a U shaped piece of springy sheet metal (shielding). Pull it off and the relay is revealed; the clear plastic cover is retained by 2 plastic clips midway on it's long axis. The relay closes and shorts the signal wires when it is de-powered (whenever power to the deck is cut or in use, when TR7 is turned off from supplying relay coil with power) Your issue is (if you're thinking of keeping your unit), to discover if the cartridge is good. You could open the relay, lift the contacts, and slide pieces of paper between them, but to do this, you would need to open up the deck which requires un-hooking the 3 leaf springs as well as opening the case (like a book, it opens). Another possibility is a broken signal wire at the relay-board terminals; the tiny coaxial cables from the tonearm board to the muting board have even tinier/fragile inner wires that are a bit of a PITA to repair when they break; I have had them break from handling when all is apart/loose on the bench. You might have an intermittent connection there. Your best bet is substituting carts, whether a known good one on your deck, or yours on another deck. If you're entertaining keeping your 8002, I'd run a flag up on the TT or general forum with that query ASAP __________________ Yamaha C2-x, TX1000, PX-2; B&O 8002/mmc1&2, Voice, Benz Glider; Marantz DV 9500; Krell FPB 300/B&W Naut 801s You frustrate me! I have tried to assist you several times yet you don't remember it OR the information (based on you're still looking for that info). And I sent you the part you needed FOC. At some point you should work on your reading comprehension, then study up on basic circuitry and electriics, then get a DVOM and a soldering station. Then maybe we can make some progress.