Hello John. The filament windings should be on the outside and should be fairly easy to remove and or replace. I have done it many times. You have nothing to lose. Drive out a coupla laminations and pull the e and i out. Then peel it like a onion and fix it.Use Scotch plastic tape and put er together again. It will work as new. 73 Mike k4XM ----- Original Message ----- From: "John Lawson" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: <amradio@mailman.qth.net> Sent: Friday, November 25, 2005 12:36 PM Subject: [AMRadio] Want Ranger pwr xfmr
> > > Anyone happen to have a NOS or Good-Used Ranger power transformer for > sale? I need one - or a Good-Used Ranger - or, a new hobby... ;} > > > After several hours on the bench last night - it is apparent why this > old girl was shelved - it came to me with a 5R4 in the HV socket, but the > fils didn't light, tho the tube was good. So sure enough - someone had > tied the 5V fil lines back, and there was a 10-ohm 10W resistor in series > with the B+ lead. > > I made a plug-in SS rectifier, installed it, switched the rig on - and > blew both diodes and both line fuses to little bits. > > Ok. > > So I restored the original circuit - there is a definite 'under-load' > short from the HV rect fils to the HV winding. > > Ok.. > > Disconnected all that - the LV side works fine, Osc runs, buffer runs - > can 'zero-beat' to a receiver, frequency of VFO seems accurate. > > Ok... > > Tansformer voltage and resistance checks are within 10% of spec. > > Ok.... > > Put new diodes in put a Variac and ac ammeter in the mains line, turned it > up slowly - POW. Actually, with the diodes in cicuit, it appears to the > Variac / AC Ammeter that the power transformer has a dead short. Having > replaced the filter caps, and checked the plate choke - it ain't them. The > B+ line resistance is slightly over 20K. > > Ok.......! > > In this process the power transformer has begun to get slighly warm, so > I went back to checking the LV side - as I was testing, the transformer > started to arc internally - and resistance measurements now show the > fil-to-HV short. So: It's toast.
