Yamaha PM2000 external PSU caps

[Ghaleon]

Hey all,

I'm picking up a 24ch pm2000 soon, and I want to order caps for the entire board so I can stay busy as soon as the board arrives.

Here's a great resource for anyone dealing with the modules: Recapping a Yamaha PM2000

I'm wanting to start with the external PSU however. Hoping someone has a cap list for the PSU, and some advice on what caps to use?

Thx in advance!

 

[Whoops]

and some advice on what caps to use?

Use Panasonic Electrolytic caps rated at 105 degrees, any series from Panasonic rated at 105 degrees is really good.

Don't go for the snake oil of "audio caps", "premium caps", "Nichicon muse".
Panasonic high end series are already premium but priced correctly not overpriced.

order the caps from Mouser or Farnell

 

[ccaudle]

order the caps from Mouser or Farnell

Original poster is in North America, so DigiKey is worth checking as well. DK is usually my first stop, decent prices, good selection, and quick shipping.

 

[sodderboy]

Totally agree, have been Panasonic 105 going on five decades. They got away from axial, so Phillips took up the slack in my bins.
Talking PSU’s, Panasonic does not fit the bill for “snap-in” or threaded style larger value caps found in them. I always have to pick an alternate.
Any re-cap list with replacement part numbers is old because sizes and availability change weekly.
With radial snap-in and thru-hole select higher voltage rating to get the proper leg spacing.
In any psu, check, clean, and re-tension any electro-mechanical connections because many problems begin there.
Mike

 

[Khron]

Aren't two-legged snap-ins pretty much standardized to 10mm pitch?

 

[Ghaleon]

Thx for the help thus far guys. I've used digikey for years and they have never let me down.

My tech friend also suggested replacing the voltage regulators?

Here's the PM2000 schematics for anyone wondering: http://www.rylandbouchard.com/files/PM2000-Schematics.pdf

 

[Whoops]

My tech friend also suggested replacing the voltage regulators?

I'm curious about the reason for that, could you ask him why?

I never had to replace Voltage Regulators besides the times they fail due to other component fails in the circuit or shorts, or wrong voltage/polarity applied.
I never have any voltage regulator fail on their own.

Maybe other people have a different experience or info so it's good to know

 

[RoadrunnerOZ]

I'm curious about the reason for that, could you ask him why?

I never had to replace Voltage Regulators besides the times they fail due to other component fails in the circuit or shorts, or wrong voltage/polarity applied.
I never have any voltage regulator fail on their own.

Maybe other people have a different experience or info so it's good to know

The ones that I have experienced to fail are the 78xx and 79xx series in the smaller packaging like TO220 without a heat sink or if a bridge rectifier has failed and has spiked the regulator. PCB mounted in free air are the most common to go but this occurs only after years from manufacture if they run hot.
Or if in a unit that uses an external wall-wart supply, onboard regulators are used to set digital and analog voltage and someone plugs in the wrong supply.
I have rarely had the TO3 versions fail.
If they’re working and voltage and ripple is normal leave them alone. Replace them when they blow.

 

[Brian Roth]

It's not all the time, , but 20/30/40 year old 78xx and 79xx TO220 regulators are a semi-common fault I see. Check date codes.... "that date on that bottle of milk means it is sour!" lol



Bri

 

[RoadrunnerOZ]

Hoping someone has a cap list for the PSU

Power supply relay:
470uF 25V x 2

+ 24V general circuits supply:
15,000uF 80V x 2
47uF 50V x 2
10uF 50V x 4

+ 32V supply spear off same xfmr secondary as + 24V:
220uF 80V x 4
10uF 80V x 2

+48V phantom supply:
4,700uF 80V x 1
220uF 63V x 2
10uF 63V x 1

+10V meter lamp supply:
1,000uF 16V x 3

+16V ch, pgm, matrix lamp supply:
4,700uF 80V x 1
220uF 50V x 1
220uF 25V x 1
33uV 25V x 1

+24V headphone amp, relays, peak ind supply:
470uF 25V x 1
220uF 50V x 1
10uF 35V x 1

This is the list of electrolytics.

Then there are more - ceramic caps:
+ 24V
0.0056 V?? x 2
0.01 630V x 4
0.1 V?? x 5

+48V
0.0047 500V x 4

+10V
0.0047 500V x 2

+16V/+10V
0.0047 500V x 2

 

[RoadrunnerOZ]

There are only 2 regulators in the whole supply - these are low current devices controlling high power regulator transistors in the + 24V supply - Toshiba TA7084AM and TA7085AM. The rest of the supply is all transistor regulation - no normal voltage regulators as you may possibly be thinking of.

 

[Ghaleon]

Power supply relay:
470uF 25V x 2

+ 24V general circuits supply:
15,000uF 80V x 2
47uF 50V x 2
10uF 50V x 4

+ 32V supply spear off same xfmr secondary as + 24V:
220uF 80V x 4
10uF 80V x 2

+48V phantom supply:
4,700uF 80V x 1
220uF 63V x 2
10uF 63V x 1

+10V meter lamp supply:
1,000uF 16V x 3

+16V ch, pgm, matrix lamp supply:
4,700uF 80V x 1
220uF 50V x 1
220uF 25V x 1
33uV 25V x 1

+24V headphone amp, relays, peak ind supply:
470uF 25V x 1
220uF 50V x 1
10uF 35V x 1

This is the list of electrolytics.

Then there are more - ceramic caps:
+ 24V
0.0056 V?? x 2
0.01 630V x 4
0.1 V?? x 5

+48V
0.0047 500V x 4

+10V
0.0047 500V x 2

+16V/+10V
0.0047 500V x 2

Cheers! exactly what I needed

 

[RoadrunnerOZ]

Cheers! exactly what I needed

80V caps may be difficult to find but 100V are readily available and also much smaller footprint today compared to the earlier ones used in this console so upping the voltage won’t necessarily mean larger capacitors.
I would suggest waiting to order until you get the console and open up the power supply - some of the larger caps are probably mounted off-board and mounted with clamps to the chassis and also some will be radial, some axial.
I’d also check all modules and look for any swollen capacitors and replace them.
I can’t remember exactly how the PSU is configured as it was a couple of years ago I last worked on one, although I have another I will be working on to restore in a few weeks once it has been moved into a newly built studio but I do have access to look at the supplies if you have any queries.

 

[Ghaleon]

80V caps may be difficult to find but 100V are readily available and also much smaller footprint today compared to the earlier ones used in this console so upping the voltage won’t necessarily mean larger capacitors.
I would suggest waiting to order until you get the console and open up the power supply - some of the larger caps are probably mounted off-board and mounted with clamps to the chassis and also some will be radial, some axial.
I’d also check all modules and look for any swollen capacitors and replace them.
I can’t remember exactly how the PSU is configured as it was a couple of years ago I last worked on one, although I have another I will be working on to restore in a few weeks once it has been moved into a newly built studio but I do have access to look at the supplies if you have any queries.

 

[Ghaleon]

Recieved the console yesterday! And yes I plan to up the voltage on as many caps as I can

Also looking at a new rectifier possibly?

 

[RoadrunnerOZ]

Recieved the console yesterday! And yes I plan to up the voltage on as many caps as I can

Also looking at a new rectifier possibly?

If you can get the KDH25-04 bridge or the S5151 dual diode blocks or the other ones, or whether you replace them all with discrete diodes and as the originals may be hard to track down let alone getting the datasheets to work out voltage/current/characteristics for replacement - if they’re working, the voltage is right for each rail and you aren’t getting switching noise from these diodes maybe just leave them. Check the DC rails with an oscilloscope and see what the ripple is like before and after re-capping the supply.

 

[Ghaleon]

update!

So I've gone through the power supply and replaced all the electrolytics, including the massive ones. I'm measuring DC output voltage at the rear PSU connector before I hook it up to the console:

Pin 4 = 28.5v
Pin 5 = -22.3 V
Pin 6 = 41.2 V
Pin 8 = 17v
Pin 10 = 25v
Pin 13 = 13v

My main concern are the +/- 24V rails. Using the lower trim pot, I was able to get Pin 5 dead on -24V. I was hoping to do the same with the higher trim pot for the +24, but it dosent seem to move from 28 ish volts.

So far I've replaced the upper trim pot, and a 36k resistor close by that was reading 33k.

Any ideas why the +24V rail won't move from 28ish volts? I have a second power supply here in decent condition, so I can swap out any parts as needed.

 

[RoadrunnerOZ]

Check the voltages around TR1 & TR2. TR1, TR2 or IC1 are likely culprits - I’d pull the transistors first and check them with a transistor tester/meter - IC1 is the regulator but I wouldn’t swap that until you check the transistors. Also check the 6K8 in series with the 36K and trimpot and also the 2K2 between the emitter and base of TR2.

 

[Ghaleon]

Check the voltages around TR1 & TR2. TR1, TR2 or IC1 are likely culprits - I’d pull the transistors first and check them with a transistor tester/meter - IC1 is the regulator but I wouldn’t swap that until you check the transistors. Also check the 6K8 in series with the 36K and trimpot and also the 2K2 between the emitter and base of TR2.

appreciate the help!

The 6k8 did test fine, I'll check out the other stuff when I get home from my day job

 

[Ike Zimbel]

Check the voltages around TR1 & TR2. TR1, TR2 or IC1 are likely culprits - I’d pull the transistors first and check them with a transistor tester/meter - IC1 is the regulator but I wouldn’t swap that until you check the transistors. Also check the 6K8 in series with the 36K and trimpot and also the 2K2 between the emitter and base of TR2.

...and check the trimmer itself. I've seen plenty of trimmers go bad after 40 years.