Yamaha PM2000 external PSU caps

[Ghaleon]

You can hear FB1 from the matrix section without issue.
If you can hear/see the FB-1 signal out of a matrix output, it means that all of the FB-1 electronics on the FB/Echo module are good. The fault is either in the output transformer for FB-1, or the wiring to/from the transformer. The metering is picked off just after the transformer, ahead of the XLR, while the Matrix signal is picked off just ahead of the o/p transformer.
Edit: I suppose there's also a chance that just the meter switching is bad...have you actually looked at the o/p from the XLR, or just used the meter to see if it's working?

great info about the matrix output.

I routed the FB1 output to my DAW/speakers, and the meter does appear to accurately reflect the sound level. Needle barely moves and Im hearing a very low signal, but the needle does indeed move, and the output is definately there!

To note - if you crank the level of FB1 the meter still moves as described above, but the peak light comes on in a normal fashion (relative to the other FB meters)

 

[Ike Zimbel]

great info about the matrix output.

I routed the FB1 output to my DAW/speakers, and the meter does appear to accurately reflect the sound level. Needle barely moves and Im hearing a very low signal, but the needle does indeed move, and the output is definately there!

To note - if you crank the level of FB1 the meter still moves as described above, but the peak light comes on in a normal fashion (relative to the other FB meters)

That seems to point to the transformer. The next step is to identify it, and then thoroughly check the wiring to it. In my experience it's rare for a transformer like that to fail, but it could happen. That said, the wiring getting pinched or otherwise mauled somewhere (like the hinge for the meter bridge) could also happen. You could try testing for a short across the o/p XLR, but bear in mind that you will see the DCR of the transformer too. Getting that number from a good o/p for comparison purposes will be helpful. And finally, if the transformer has actually failed, you could steal the one off the Phones o/p to replace it.

 

[RoadrunnerOZ]

I routed the FB1 output to my DAW/speakers, and the meter does appear to accurately reflect the sound level. Needle barely moves and Im hearing a very low signal, but the needle does indeed move, and the output is definately there!

To note - if you crank the level of FB1 the meter still moves as described above, but the peak light comes on in a normal fashion (relative to the other FB meters)

The peak indicator takeoff is pre transformer, the VU meter takeoff is post transformer - the low output level indicates either wiring/joint failure/high resistance to the input at the transformer- or from the output of the transformer to the takeoff point for meter and XLR - or the transformer has internally failed in some way - maybe burned windings causing shorted turns or high resistance leakage feedthrough.
As Ike said you can try swapping in another transformer.

There is also a small possibility that the peak LED circuit or the meter coil is causing a problem - try switching the metering to Echo1 from FB1 and see if the output level from the FB1 XLR jumps - up (you won’t have metering but you will have signal) if the level remains low then it’s not the LED circuit or meter. The switch transfers the meter and the peak LED together. (Note: If Echo 1 works normally then it’s not the LED circuit or meter shorting the signal)
This is easily visible in the Foldback Phone Module schematic.

 

[Ghaleon]

The peak indicator takeoff is pre transformer, the VU meter takeoff is post transformer - the low output level indicates either wiring/joint failure/high resistance to the input at the transformer- or from the output of the transformer to the takeoff point for meter and XLR - or the transformer has internally failed in some way - maybe burned windings causing shorted turns or high resistance leakage feedthrough.
As Ike said you can try swapping in another transformer.

There is also a small possibility that the peak LED circuit or the meter coil is causing a problem - try switching the metering to Echo1 from FB1 and see if the output level from the FB1 XLR jumps - up (you won’t have metering but you will have signal) if the level remains low then it’s not the LED circuit or meter. The switch transfers the meter and the peak LED together. (Note: If Echo 1 works normally then it’s not the LED circuit or meter shorting the signal)
This is easily visible in the Foldback Phone Module schematic.

Just tried this, level remains the same. can't hear any kind of volume spike when the meter is switched

 

[RoadrunnerOZ]

Can you swap a transformer?

 

[Ghaleon]

Can you swap a transformer?

As Ike suggested, I dont think ill miss the phones trafo.
Next time I have access to the back, I'll check all the wires + connections to the FB trafo, and do the swap

 

[RoadrunnerOZ]

If it turns out to be the transformer and you poach the phones transformer, then you can always use a third party 600:600 transformer for the phones output rather than paying silly prices for the original Tamura - the phones out is mono and a +4 output for maybe a headphone amp? Likely you’ll never use it anyway.

 

[RoadrunnerOZ]

For a decent phones system you could just use one of the stereo phone jack outputs feeding a headphone amplifier - (the XLR mono phones out is taken as a mix of the two left and right inputs to the phones amp chips and summed to mono) - this would give you a stereo phones system for recording. Headphone amps usually will accept headphone level signal as well as line level. The stereo phones 1 & 2 on the Yamaha are designed to drive 8Ω cans.

 

[RoadrunnerOZ]

I would also check that IC9 on the FB2 board has correct output - you can check with a scope at the 100uF bipolar cap that feeds the transformer or at the connector that feeds the transformer - best to check with the transformer connected then disconnect it and check again - it’s possible the NE80100 is faulty and the peak LED is lighting with spikes and not proper audio level. Did you replace or check the 100uF?

 

[RoadrunnerOZ]

Other than that, I'm starting to look at the eq's if anyone has some guidance. I know about the JLM inductors, and Flying Eye has thier own version of an inductor mod.

JLM is a company I have purchased off many times and so far all the stuff I have purchased has been of high quality. I assume this is the kit you are talking about?:
https://www.jlmaudio.com/shop/pm2000-eq-mod-kit.html?display_tax_prices=1This would be costly for doing a mod to all channels and also a lot of work so if you’re seriously looking at doing it I’d get a couple of kits at first as a test and mod two channels and see what it sounds like on a full program stereo signal and with mono mic tests plus other things like acoustic guitar with pickup or pickup/preamp (with the guitar EQ flat).
Look at the install instructions - they provide photos of the step by step fitout - you need to be sure that you want to do this as it need to be done with the channel card selector boards in place and it’s a major to take the boards out to fit to.

 

[RoadrunnerOZ]

I’ve done a few console mods and the best way I’ve found is to take all modules out in blocks of 8 then perform the same task to each one in sequence - strip components 1-8, mount board 1-8, fit wiring 1 1-8, fit wiring 2 1-8, etc. Having done a Jellinghaus C-Mix automation retrofit to 2 linked Tascam M3500 32 channel consoles, which I fitted inside the console chassis under the faders instead of fitting the supplied big box underneath the console, which I found would hit the knees - this had to be done to the whole lot of channels at once and was a big job. It came to doing everything in an assembly line fashion, each task repeated 64 times - repetition made it easier to not make mistakes and checking back down the line was only for one thing at a time. When I switched it on for the first time it all worked perfectly. Took two days, 1/2 a bottle of Jack and lots of takeaway food

 

[Ghaleon]

I would also check that IC9 on the FB2 board has correct output - you can check with a scope at the 100uF bipolar cap that feeds the transformer or at the connector that feeds the transformer - best to check with the transformer connected then disconnect it and check again - it’s possible the NE80100 is faulty and the peak LED is lighting with spikes and not proper audio level. Did you replace or check the 100uF?

yup that module was fully recapped! I'll have a look with the scope

JLM is a company I have purchased off many times and so far all the stuff I have purchased has been of high quality. I assume this is the kit you are talking about?:
https://www.jlmaudio.com/shop/pm2000-eq-mod-kit.html?display_tax_prices=1This would be costly for doing a mod to all channels and also a lot of work so if you’re seriously looking at doing it I’d get a couple of kits at first as a test and mod two channels and see what it sounds like on a full program stereo signal and with mono mic tests plus other things like acoustic guitar with pickup or pickup/preamp (with the guitar EQ flat).
Look at the install instructions - they provide photos of the step by step fitout - you need to be sure that you want to do this as it need to be done with the channel card selector boards in place and it’s a major to take the boards out to fit to.

Yes, starts to get pricey. I think the flying eye ones also mod the high eq as well, for a total of 3 bands. If I really like the sound I think id be up for making the investment. However, buying a boatload of film caps and nice resistors would be much cheaper. Just a lot of time and energy soldering. I'd like to know if anyone went the eq pcb recapping route, and if they were happy with the result

 

[RoadrunnerOZ]

yup that module was fully recapped! I'll have a look with the scope

Yes, starts to get pricey. I think the flying eye ones also mod the high eq as well, for a total of 3 bands. If I really like the sound I think id be up for making the investment. However, buying a boatload of film caps and nice resistors would be much cheaper. Just a lot of time and energy soldering. I'd like to know if anyone went the eq pcb recapping route, and if they were happy with the result

Different result with the inductor mod though - changes the Q of the circuit, widens the band. Don’t think you’ll achieve the same result with resistor/cap mod. Also I think the PCB add-on of JLM Audio is easier than the resistor/capacitor refit - think of the access with wiring that’s easy to burn with the iron. When I have done in place mods I’ve taped heat mat to the looms and other boards so I don’t burn things - I just cut up the silicone mat into squares and strips - got the soldering mats for $3 off AliExpress

 

[RoadrunnerOZ]

If you look at the flying eye mod that’s a major takedown and rebuild per channel - you’d be at it for months.
Edit: from what I’ve seen but maybe there’s something I missed?

 

[Ike Zimbel]

As Ike suggested, I dont think ill miss the phones trafo.
Next time I have access to the back, I'll check all the wires + connections to the FB trafo, and do the swap

Here's an idea: Use a FXLR-FXLR turnaround to run the output of a working output, say, Group-1, into the FB-1 output and select FB-1 on the VU meter. If the meter shows signal, you have ruled out another variable, the wiring between the output side of the transformer and the XLR/meter. If it doesn't show signal then look at that wiring first. It has occurred to me that it could also be a broken wire feeding the transformer, from the backplane. That wire should be close to where that module plugs into the backplane.

 

[RoadrunnerOZ]

Sometimes those crimp terminated connectors also corrode inside the crimp and give a high Ω reading, not sure how the termination runs from the backplane to the transformer board - but worth doing a point to point with a meter.

 

[Ghaleon]

If you look at the flying eye mod that’s a major takedown and rebuild per channel - you’d be at it for months.
Edit: from what I’ve seen but maybe there’s something I missed?

I think the flying eye thing is a lot like the JLM pcb. It just adds another band to inductor. I've been speaking with Chris and wanted more details but he's a busy guy!

 

[RoadrunnerOZ]

I think the flying eye thing is a lot like the JLM pcb. It just adds another band to inductor. I've been speaking with Chris and wanted more details but he's a busy guy!

Could be an improvement then.
You’ve just got to look at the cost across the whole board and the total down-time. In mods I’ve done a few where they only wanted a handful of channels done for specific purposes - waste of time and money doing the whole console but that was for one section devoted to things like vocals and acoustic instruments so about 8 - 12 channels done, the rest left alone - it is nice to have all channels the same especially with a marked sonic improvement. Can boost the resale value too.
Still I’d get the whole board working first and then when it’s all working have a good listen to see what EQ improvements could achieve.

 

[RoadrunnerOZ]

That’s why I would suggest just doing two channels as a test - see if you like the mod without breaking the bank and finding you’re down with no console for a long time. Do one to work out procedure for a big run, stopwatch the second to get a time estimate on total downtime. Because I’ve done mods in a studio environment and not on a nice workbench I’ve found 8 channels at a time is about max - couple of 6 1/2 foot folding picnic tables as a workspace.