OTR Micro, blew quickly (there are two fuses)
Replaced shorted cap w/used - within .02uf, w/ matching diode.
Days later, low power; "HVT" fuse not full voltage at both ends (weird).
1 month later; ran, no heat. I removed control panel, tried for at least 5 minutes to heat a coffee, "Main" and "HVT" fuses 120v both ends.
So I replaced the panel and left for work. Cooking attempts were made, lights/power/display quit. Found "Main" fuse blown.
Next test, the "HVT" blew in a few seconds.
I moved mw to bench and tested using an old Triplett 630-PLK type 6 w/ two batteries (one is 30v), and a Radio Shack 22-221 (analog).
MAG filament; 0 Ω. Filament to chassis; ∞ (both meters).
CAP; R/S - 200k to ∞ both ways. Triplett (x100k range) - near 0 to 9000k (both ways). Should go nearer 0? And to ∞, not 9 mega-ohm?
DIODE; R/S - ∞ both ways. Triplett (x100k range) 85k one way, ∞ other. Should be less than 85k? (wouldn't blow fuse if open though)
HVT Filament winding - 0 Ω. Filament to chassis - ∞ (both meters).
Secondary - R/S; 350Ω, Triplett; 500Ω (mw paper says "Approx. 90Ω).
Primary; This has three wires at primary; blk, wh, and a blue between them. Apparently the blue's tapped in the middle for "low" power? It goes through the "HV" fuse to a relay that has the other wire white. The paper found in the mw simply says "Primary winding Approx. .3Ω".
wh/blk; R/S - 0Ω. Triplett - .6 Ω, then trips "protection" button.
wh/blu; R/S - 0Ω. Triplett - .2 Ω.
blu/blk; R/S - .5 Ω. Triplett - .5 Ω then trips "protection" button after varying amounts of time from instantly to 10 seconds or more. I tried leaving the R/S meter attached (set to 5vdc - it's lowest range) to see if there was voltage somehow being induced and tripping the protection, and the needle did move a tiny bit.
The original fuses were "BUSS MDA 20A", replacements were "BUSS ABC 20A", after running out, I'm using 20 amp glass fuses - could it be it just needs the correct "time delay", or "slow blow" fuses?
Though my ohms readings are mostly "off", online info says testing the HV components is best done by replacing with "known good" parts - are there ways I can run mw with certain things disconnected to pinpoint the problem (without electrocuting myself)?
I couldn't find info on the three-wire primary until I searched "inrush relay" (one of three relays shown in schematic). Could I try (for example) disconnecting the primary wires, run cook cycle, then introduce 120v to the black & white or black & blue terminals with a separate cord? Wouldn't this eliminate problems in switches, relays, etc. that occur only under load?
Any ideas would be appreciated.