My old dmr ez27 died a couple of years ago, and I’m getting around to fixing it. The front panel display gets progressively dimmer, and then it shuts down after 15 minutes of operation. My guess is that it is a power supply problem. Has anyone else seen this problem? I’m inclined to replace all the supply capacitors. It looks like there are a dozen or so aluminum electrolytics and half a dozen tantalums (gum drops). Before I commit, I’d appreciate hearing from someone who’s been there already.
I’m replying to my own post because I have found and resolved the problem. I found two aluminum electrolytic capacitors that appeared faulty; their tops were slightly convex while all of the rest were very flat. They were 470uF and 680uF, both with a 16V rating. I replaced them with capacitors with 35V ratings. 24 hours later everything is still good. The unit stays fairly cool and operates properly.
(Nudging thread to a more appropriate forum section)
Were they in the power supply as you suspected, or did they somehow manage to appear further down the line?
Albert, both failed capacitors were in the power supply. The ez27 has now been operating well for several days. When I started the repair, I ordered replacements for every aluminum electrolytic capacitor. I only replaced the two that showed visible damage, and then I tested. The desoldering is not easy, as lead-free solder is used. Its higher melting temperature makes it somewhat challenging to rework. I felt that it would risking damage to the circuit board to replace all of the capacitors.