Memorymoog Power Supply woes (solved)

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electrojoe
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Re: Memorymoog Power Supply woes

Post by electrojoe » Thu Jan 28, 2016 4:33 pm

Hi Guys,
The polymoog had 2 different versions of the power supply, but the memorymoog only had the one version, which is a modified version of the final version of the polymoog power supply, hence the incorrect pin numbering.

In the schematic, there is 1 connection coming from the + connection of C4 after the +15 diode bridge, that runs down and connects to VC and V+ on IC3, the 723 for the +5 volt section.

Also, looking at the power supply with the 15 pin connector facing me, the center trimmer is for +15 volts, the left is for +5 volts and the right is for -15 volts.

Hope this helps.
Gerry

zaiusz
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Re: Memorymoog Power Supply woes

Post by zaiusz » Thu Jan 28, 2016 4:38 pm

Lol, I think you are right, the far left is the -15. I think I'm wrong... just trying to go by memory but I know that the far right is for sure the 5volt. The schematics just add to the confusion because according to them C4 is on both the + and the - 15 volt section. I think in the -15 C4 is supposed to be C1.

Anyway, so this path from C4 that goes into R24, is that driving the 5v somehow then?
Last edited by zaiusz on Thu Jan 28, 2016 4:41 pm, edited 1 time in total.

zaiusz
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Re: Memorymoog Power Supply woes

Post by zaiusz » Thu Jan 28, 2016 4:40 pm

deleted

electrojoe
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Re: Memorymoog Power Supply woes

Post by electrojoe » Thu Jan 28, 2016 4:47 pm

Hey,
Your right, they are both labeled C4 in the Schematic, (those norlin folks, huh?!).

Yes, the +15 raw voltage is sent to the 723 IC in the 5 volt section to provide power for that IC, if it is not there, the +5 volt section will not power up.

Gerry

zaiusz
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Re: Memorymoog Power Supply woes

Post by zaiusz » Thu Jan 28, 2016 4:55 pm

Thanks Gerry, that is a good clue for me when I get to take a stab at it next.

Appreciate all the interest and input from you guys in helping me out, thanks!

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noddyspuncture
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Re: Memorymoog Power Supply woes

Post by noddyspuncture » Thu Jan 28, 2016 5:07 pm

zaiusz wrote:Thanks Gerry, that is a good clue for me when I get to take a stab at it next.

Appreciate all the interest and input from you guys in helping me out, thanks!


Check that R24 470 ohm...!
By the way I must be looking at a different schematic to you guys... on mine I have a C1, a C4 and a C7 smoothing caps...!

Cheers,
Tom

Brian G
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Re: Memorymoog Power Supply woes

Post by Brian G » Thu Jan 28, 2016 10:39 pm

Was it here someone posted that a person has made a new power supply for the Memorymoog ?
In the processes of having mine recapped, then try and deal with other issues.

zaiusz
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Re: Memorymoog Power Supply woes

Post by zaiusz » Fri Jan 29, 2016 11:56 am

There was a post on a forum somewhere on the net, a guy named Chuck Wagner can arrange it. A quick google search will bring him up, and it runs about 295 euros. I've been in touch with the guy about it and I'm highly considering this option at this point, I remember the fan noise in the MM is like an idling airliner. There is a wait for the supply though.

In the mean time, my compulsiveness compels me to sort out my original PS.. and it will be more cost effective to sort this one out for now.

zaiusz
Posts: 47
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Location: Torontoish

Re: Memorymoog Power Supply woes

Post by zaiusz » Fri Jan 29, 2016 10:58 pm

electrojoe wrote:O.K.
First, you need to have the +15 volt power section active, because, the 5 volt regulator gets it’s power from the +15 volt supply.
Second you need to connect the sensing lines for all voltages.
So for best test results, connect all 3 AC power connectors.
Using the pin numbering I suggested earlier ( Pin 1 on the left, pin 15 on the right) do the following.

Pins 1-2 connect together and that is +5 volts
Pins 3-4 connect together and that is Ground for +5 volts
Pins 7-8 connect together and that is Ground for +15 volts
Pins 9-10 connect together and that is +15 volts
Pins 12-13 connect together and that is –15 volts
Pins 14-15 connect together and that is Ground for –15 volts.

Then connect the 3 Grounds together, and use that as your test ground reference.

This should give you the voltages you are looking for.

Gerry


OK! Followed your steps and put a nest of alligator clips in there, and I have correct power on each rail. Thank you! Now, time to figure out what else is wrong lol.

zaiusz
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Re: Memorymoog Power Supply woes

Post by zaiusz » Fri Jan 29, 2016 11:37 pm

Well, I'm making progress but something is definitely wrong. I see "MOOG", all the panel lights seem to work though somewhat glitchy, can scroll through patches, 6 tuned, no sound but BURNING SMELL coming from the left panel. Boy, I was hoping that getting the correct voltages outta the power supply would be it, but looks like I'm going to have to go full tech on this thing.

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noddyspuncture
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Re: Memorymoog Power Supply woes

Post by noddyspuncture » Sun Jan 31, 2016 5:56 am

electrojoe wrote:O.K.
Second you need to connect the sensing lines for all voltages.


This is what I was talking about earlier. Very similar to working on the CS80 power supply when not connected up.
If you don't connect the sensing lines than damage can be caused to the supply...!

Cheers
Tom

electrojoe
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Re: Memorymoog Power Supply woes

Post by electrojoe » Sun Jan 31, 2016 12:19 pm

Hello,
Double check that you have all of the transistors secured to the heat sink.
If all of that looks good, you may have to look at the current draw for each rail to see where the excess current is coming from, causing heat generation.
Once you identify the extra current draw, you will need to focus on that power rail and items connected to it.

The +15 and -15 rails should be drawing about 1.0 to 1.2 amps, and the 5+5 rail should be pulling about .9 amps.
If you have a MM+ the +5 rail will be a little higher.

Hope this helps.

Gerry

zaiusz
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Joined: Mon Mar 05, 2012 10:58 pm
Location: Torontoish

Re: Memorymoog Power Supply woes

Post by zaiusz » Mon Feb 01, 2016 12:08 am

Ok, I suppose that will be my next step- check the current draw. Very good to know about the connecting sensing lines together, I didn't see a single mention of doing this in my service manual. All it said was to disconnect p131 if you have a complete loss of a line and measure between specific pins. I hope this info helps someone out in the future too.

I'm sure that once I hook it up again it will blow something though, I was listening through headphones to see if I got sound and there was a buzz that was increasing in volume and the smell worsened.. I disconnected the power before anything major happened. I'm sure this was a sign of something ready to pop. I couldn't really tell if the burning smell was the power supply or the LSC board, I removed the LSC board to see if I could smell something but couldn't. Couldn't see any sign of burning either. I wonder if one of the 3 78M06 regulators were about to die... looking at them I'm surprised they grommetted the heat sync on them.. not an easy way to replace if needed.

atomicsynth
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Re: Memorymoog Power Supply woes

Post by atomicsynth » Wed Feb 03, 2016 12:00 pm

I strongly recommend you abandon fixing that oven of a supply, period, and replace it with the Heinz Weierhorst switching supply. Good thing I looked and saw this thread because that stock supply is simply not good for the synth and yours has failed.

This is a no brainer decision. It is rev.2 of the rev. 1 supply sold by Synthtaste to their approved service centers only. This new supply was designed by Heinz Weierhorst who was formerly associated with Synthtaste but is now working on his own and selling direct to end users at less than half the price of the Synthtaste unit.

This supply can also be adapted by Heinz to go in Jupiters, Prophets, Polymoogs, Chromas and other synths.

The supply is built in Germany. It is €250 plus shipping. They are built individually per order and previous orders are presently being filled as payment is received. In advance to the designer/builder Heinz Weierhorst is preferred but one can be built upon 50% advance and remaining due prior to shipment.

In the Memorymoog, no more fan, heatsink, transformer or fuse. The new switching supply is SMD design, state of the art and will outlive the synth.

Installation instructions ship with the supply. If you've worked inside your synth you can do it or defer to a tech. Four holes do need to be drilled in the synth chassis.

The digital board of the Memorymoog is modified in a few places on the top side of the board as the supply actively controls the reset circuit of the synth, fully protecting the ram, CPU and Curtis devices. The supply eliminates heat since the old oven of a power supply is gone. The synth is much more stable given the precision of the new supply which arrives fully assembled, calibrated and will have been burnt in under load for a week prior to shipping.

From switching on under load for one hour, deviations are only
+5V 0.05%
+15V 0.004%
-15V  0.002%
Outstanding specs! Power comsumption is 45.5W only; approx half of the original supply.

If you intend to order I'll forward your intent to buy on to Heinz who will contact you directly regarding payment and build time in queue.

Because the heat sink will be gone you'll need a perforated aluminium panel to cover the heat sink space as the ventilation is recommended even though the supply runs literally hand warm.

You can order one from Heinz at modest addtl cost or secure one on your own.

Use my [email protected] email for serious intent to order or send a direct on instagram Don't PM me here as I don't check this forum regularly.

Direct photo links.

https://www.instagram.com/p/6UKBtkqQ08/

https://www.instagram.com/p/55BWduKQ7o/

https://www.instagram.com/p/5WGgCdqQ7S/

https://www.instagram.com/p/4PtWf5qQ4w/

https://www.instagram.com/p/55B71LKQ9H/

zaiusz
Posts: 47
Joined: Mon Mar 05, 2012 10:58 pm
Location: Torontoish

Re: Memorymoog Power Supply woes

Post by zaiusz » Thu Feb 04, 2016 11:23 pm

Thanks Chuck. Still considering that. But I think my problems with the PS are fixed, and have new problems to worry about...


In other news, I'm still at the point of trying to see how much drain there is from the supply in amps.

So noob moment here, I can't seem to get a reading using the mA setting on my DVM. Never had the need to use this mode before so am I right in assuming the procedure is the same as reading volts? Can't see any amps at all on the 5v rail. The other rails are inconsistent too. I tried reversing the probes and could get -.9mA on my -15 rail but the other way around its only like .03mA. Made sure my DVM is set to measure DC mA too, not in AC mode. Maybe this thing is broken, has been acting a little unusual lately.

Since last time I put in new smoothing caps on the LSC board and new regulators. Still smelling something cooking though. Hard to tell where from, but in the vicinity of the PS & LSC. Everything looks ok on the panel though-- LEDs, Screen, Lfo blinking etc. Meaning my digital side must work, I can change patches and program numbers and all that but I don't hear any sound and theres that smell. Thankfully no smoke yet.

Maybe I'm taking the smell too seriously, maybe its the smell of new heatsync compound being heated by hot power transistors, but it sure does become pungent the longer its on. No idea... :?
Any further advice to a man with his first MM experience?

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