Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Restaurant at the End of Universe Hitchhikers - Service, Repair, Custom Leads & Interfaces DSP5200 non-SL recap

Sounds right and the case from the 90s through the 2000's regarding the design choices around the regulators. The resistor choices on my M60 and 5000 regulators divided a large amount of voltage across the regulators, unnecessarily, either from regulator IC aging or poor design. That and the use of non-ceramic resistors burned a hole in the PCBs. It took a lot to repair the PCBs. The original low wattage resistors were completely destroyed. I added heat sinks and adjusted the divider ratio (from memory) on the M60's but just the heat sinks and ceramic resistors are enough. Left the ratio alone on the 5000's. Should be easy to bolt on a big heatsink with your regulator configuration. I would do that.

My experience with the cap aging was similar and worse since the speakers were older. Many were essentially on their last legs. Cap tech is so much better now and we shouldn't have any issues in our remaining lifetime. I used the Panasonic FR series but any quality long life cap is fine in the power supply sections. Where space allowed I used higher rated lifetime caps (usually larger physically). The signal path caps are all non-electrolytic so no problems there, generally.

My digital board caps were fine minus the ones around the voltage step down functions if memory serves. Any electrolytics near heat are worth replacing all in one go, if not all of them.

The whole effort was time consuming, but worth it- really seemed to improve sound quality. All speakers from the 90's and 2000's need to be serviced if used even a moderate amount or left on in "stand-by." In "stand-by" the analog amps are all powered with regulators burning away and caps aging.

100% going to add heat sinks: have some on order. Thinking of possibly remoting the resistors, maybe the regulators. Funny enough, the DSP board regulator was remoted with a thermal pad chassis. Measuring the caps, accidently re-installed and pinched the wires for it running under the PCB causing the DSP power bridge to fail closed! the Hakko 301 desoldering gun made this MUCH easier. Did the replacement in 4 stages, testing after; took a good bit of time. Did not replace the amp res caps yet, they are an odd size/spacing making choices limited. Ordered 15 NOS FM off the Digikey marketplace, 4 seemed bad. Non marketplace digkey has been close to 100% perfect.





OEM caps before replacement
Caps in Amp:
10x 47uf 10v (Nichicon FW)
6x 470uf 15v (Nichicon FW)
6x 100uf 10v (Rubycon SK)
4x 6800uf 63v (Nichicon FW)
2x 2200uf 16v (Rubycon Sk)
2x 100uf 63v (Rubycon Sk)

Cap List for DSP:
3x 3300uf 6.3v (Nichicon FW)
2x 2200uf 25v (Rubycon SK)
2x 1000uf 16v (Nichicon FW)
1x 1000uf 10v (Jamicon something)

Great job!

I've seen some of the later DSP5200s where the amplifier board regulators are mounted to the back panel. That may be a simpler solution than using separate heatsinks. You'll still need the isolation washers/thermal pads.

The DSP5200s can run quite warm, and it is the heat that causes the capacitors to cook. It is worth sorting them before the capacitors totally fail, as I've seen a few boards where they've failed and taken out the output transistors.

Cheers,

Steve

Does anyone know if the newer DSP5200SE has these heat issues sorted out? I have an early 5200C non-SL and it runs pretty hot on the back panel.

Thanks Steve! I think the speakers were close to failure, both units have a 60hz hum when hot by the regulators/main caps: Regulators might be End of life. Recapped/non recapped both draw about 22-23 watts each when idle. Ever seen someone open up some holes/slots in the back for some convection air flow? Going to play around with the configurations, remote mounting with heat sinks will most likely be it.


@all_In, have not opened up my SE units, they idle and run MUCH cooler. Running for hours SE units are cooler then the Non SL units in stand by. would be nice if .2 or SE kits could still be had, would happily diy it.

I bought some circular vents from Digikey and went to town with a hole saw. Chips go everywhere so be careful to catch them.

Well played around Alot with mounting locations and cooling. Used some standoff's to mount the resistor bank off the board; looked great but 150f was dumping right on the caps. ordered some 10w chassis mount, remote mounted them to the chassis ~ heat is very under control. The regulators were... well a lot of fun, unfortunately the thermal pads i used were slightly conductive... prompting several re-mounts, leading to the not nice looking long leads. new pads fixed the short. have some clean up with the bolts for the regulators. Pending longer testing, heat sinks can be added by easily (if required).
Final regulator mounting, and remote resistor leads

Remote mounted Resistors right to chassis above DSP shield

Clean vertical mounted regulators and Resistors on standoffs