20-10-2017, 05:27 PM
Decided to have a session with the 2000 only to find that my PM5519 test pattern generator had failed. It has had a couple of intermittents for a while but gentle percussive maintenance didn't work.
Opened it up, didn't bother with the manual at this stage. Rattled the 2 connectors to the PSU board and all came back to life. Touch of servisol in both and it was fine. Then the intermittent hum problem decided to appear. Scoped the outputs from the PSU and found 50Hz hum on one of them. One of the reservoir caps also had 50Hz on it, a bit odd seeing as it's fed from a packaged bridge. In theory at least it means a diode in the bridge is intermittent but I decided to resolder the connections and this seems to have cured the problem. Gave the offending bridge a shot of freezer and it's still OK. I ought to replace it and I've got a bridge in the drawers that will fit.
Opened it up, didn't bother with the manual at this stage. Rattled the 2 connectors to the PSU board and all came back to life. Touch of servisol in both and it was fine. Then the intermittent hum problem decided to appear. Scoped the outputs from the PSU and found 50Hz hum on one of them. One of the reservoir caps also had 50Hz on it, a bit odd seeing as it's fed from a packaged bridge. In theory at least it means a diode in the bridge is intermittent but I decided to resolder the connections and this seems to have cured the problem. Gave the offending bridge a shot of freezer and it's still OK. I ought to replace it and I've got a bridge in the drawers that will fit.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
