santiagon80
New Member
hey there all youse, AK’ers of the world!
So…i got an hk330b multivoltage with a dead transformer… previous owner had already told me that smoke was coming out of it when turned on. I got it with the idea in mind that I had to replace that transformer, probably due to dead outputs, bad caps and/or a short somewhere. Then aim at a full restoration à la Doug (@dlucy style).
Schematics and service manual don’t have info on the particulars of the transformer. So I thought of a way to get some data and aid in the search for a replacement.
I removed the transformer from the receiver and hooked its secondary terminals to the multimeter, it has two pairs of secondary terminals. Then plugged the transformer primaries to the mains and quickly measured voltage. The transformer hummed loudly and started to smoke after 5 seconds plugged. That window gave me time to measure both secondary terminals: 9v at one set of terminals and 60v at the other. I measured primary terminals too before unplugging, I was getting the 230v from the mains. I also hooked the tranny to a Dim Bulb Tester with a 150W bulb, (receiver is rated at max. 180W). Bulb shone very brightly, but I measured voltages and got the same step-down ratio between primary and both secondaries. (1100 mV primary, 41 mV at one and 265mV at the other).
The measurements I got, make sense in the schematics, as one of the secondaries feeds AC to the lights, which are rated at 8v, 0.3A; and the other secondary feeds the PS board that should measure 53.5v after rectifiers.
My guess is tranny’s shorted at the primary winding.
Do you think I got enough data to get a close enough replacement? I’m thinking of getting a new transformer rated at 220-240v at the primary and two secondary outputs, 60v and 9v…
Does this sound like a reasonable approach?
I must say, I can get a custom-made transformer for cheap or maybe for free… got a guy, you know…
So…i got an hk330b multivoltage with a dead transformer… previous owner had already told me that smoke was coming out of it when turned on. I got it with the idea in mind that I had to replace that transformer, probably due to dead outputs, bad caps and/or a short somewhere. Then aim at a full restoration à la Doug (@dlucy style).
Schematics and service manual don’t have info on the particulars of the transformer. So I thought of a way to get some data and aid in the search for a replacement.
I removed the transformer from the receiver and hooked its secondary terminals to the multimeter, it has two pairs of secondary terminals. Then plugged the transformer primaries to the mains and quickly measured voltage. The transformer hummed loudly and started to smoke after 5 seconds plugged. That window gave me time to measure both secondary terminals: 9v at one set of terminals and 60v at the other. I measured primary terminals too before unplugging, I was getting the 230v from the mains. I also hooked the tranny to a Dim Bulb Tester with a 150W bulb, (receiver is rated at max. 180W). Bulb shone very brightly, but I measured voltages and got the same step-down ratio between primary and both secondaries. (1100 mV primary, 41 mV at one and 265mV at the other).
The measurements I got, make sense in the schematics, as one of the secondaries feeds AC to the lights, which are rated at 8v, 0.3A; and the other secondary feeds the PS board that should measure 53.5v after rectifiers.
My guess is tranny’s shorted at the primary winding.
Do you think I got enough data to get a close enough replacement? I’m thinking of getting a new transformer rated at 220-240v at the primary and two secondary outputs, 60v and 9v…
Does this sound like a reasonable approach?
I must say, I can get a custom-made transformer for cheap or maybe for free… got a guy, you know…
