UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Trio W-38 servicing process

qualityten · 19th Aug 2010, 6:16 am

Thanks Michael and Glen. Michael, I'll check later, but I think that without the rectifier the lamp glowed brightly immediately.

Given all the bad reports about the grey Elna caps, confirmed now by Glen, I think I must replace all the 40uF (350, 250 or 150 V) caps before continuing. For the purpose of checks would it be okay to replace them with 68uF (450V) ones, as I have a good stock of these to hand?

Thanks for the advice on resistors Glen. Phew, there would be a lot to replace. I could not get any reading from the big 220R 6W cathode resistor (I think it's R301 on the diagram), so I replaced that with new 7W one. The others on the same tag board checked fine.

The circuit diagram also makes clear the fuse should be 2A (slow blow I guess?). The one in place is illegible (printing damaged) and has been externally bypassed by a fine fuse wire which may or may not be 2A!

Thanks to all for advice so far, and again to roffe for the schematic.

19th Aug 2010, 6:16 am	#16
qualityten Octode Join Date: Feb 2009 Location: Wallasey, UK. Posts: 1,310	Re: Trio W-38 servicing process Thanks Michael and Glen. Michael, I'll check later, but I think that without the rectifier the lamp glowed brightly immediately. Given all the bad reports about the grey Elna caps, confirmed now by Glen, I think I must replace all the 40uF (350, 250 or 150 V) caps before continuing. For the purpose of checks would it be okay to replace them with 68uF (450V) ones, as I have a good stock of these to hand? Thanks for the advice on resistors Glen. Phew, there would be a lot to replace. I could not get any reading from the big 220R 6W cathode resistor (I think it's R301 on the diagram), so I replaced that with new 7W one. The others on the same tag board checked fine. The circuit diagram also makes clear the fuse should be 2A (slow blow I guess?). The one in place is illegible (printing damaged) and has been externally bypassed by a fine fuse wire which may or may not be 2A! Thanks to all for advice so far, and again to roffe for the schematic.