Hi all
As I might have mentioned I have another sick 2445, this time probably U800 as no horizontal deflection (but I *might* have a U800 in one of the parts 'scopes I also still have).
Anyway, debugging this one lasted about 10 seconds before the RIFA caps in the PSU blew their guts out, so the PSU needs some attention first.
While I have the PSU out I will take the opportunity to replace the other suspect caps and I'm contemplating a full recap but the electrolytics which are in situ look OK so..... maybe I'll leave them.
I haven't found many suspect components - though the 30ohm resistor in series with the RIFA that blew is open (as you might expect) However the NTC inrush limiters RT1010 and RT1016 seem to be somewhat higher than nominal - about 41 ohms at room temp for the "7.5 ohm" one and 15 ohms for the "5 ohm" one. Admittedly "room temp" is about 22-23 degrees C at the minute, not 25 but I've warmed both between finger and thumb and they don't get to their nominal values.
This order needs to be from DigiKey because only they stock the magic indicator switch caps and I'd like pick those up at the same time.
Ametherm SG200 looks a reasonable bet for RT1016 (supposed to be Rodan SG-6), and SG64 plausible for RT1010 (supposed to be 75DJ7R5R0220SS), or maybe Amphenol CL-50B, I don't suppose that it is terribly critical - although the Amphenol part is only rated 5A
Also, some people recommend replacing the 15ohm resistors which are in parallel with the NTCs with higher wattage ones - but I can't see the point as they will be shunted when the NTCs are up to temp. What is the group consensus?
Kind regards
Paul
