Hello, gentlemen.
I'm a newcomer to the forum, but I'm told that there's plenty of expertise represented here and I should post my question.
I have recently acquired a Hammarlund HQ-140-XA receiver that appears to be in fine physical shape, but won't light up. The previous owner told me that it's got a blown power transformer. I can confirm that it won't light up, at least. The question, then, is where could I obtain a replacement transformer for this lovely and possibly functional old radio? And, failing that, what are the secondary winding output voltages on that transformer, so I can replace it with a separate transformer for each circuit? And if I can't do either of those, is rewinding the transformer a viable option?
I can use simple hand-tools, puzzle my way through a schematic, operate a multimeter, and solder. Any advice on how to proceed would be much appreciated. Thanks in advance.
Questions about my sick hollow-state receiver (HQ 140 XA)
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Earl T. Gray
- Posts: 1
- Joined: Tue Aug 03, 2004 6:04 pm
- Location: Rocky Mount, NC
Blown Power Transformer in your HQ-140
You can get a replacemet transformer from Peter Dahl, but it'll probably cost you more than you paid for the radio. You can however, scare up one if you make enough postings on enough websites. Start with "boatanchor" radio sites. More than likely, there are lots of "parts" radios out there with good transformers.
Do you have a manual? If not, I think I have one that I would be happy to copy for you.
First, I would make absolutely sure that the transformer IS in fact bad. A Variac and some form of AC current measurement capability is a big help in that regard, but not a requirement. Since the radio appears dead, start by following the AC line cord plug with an Ohmeter. Normally, one lead goes to the transformer primary and the other is wired to the power switch, then to the transformer. You might get lucky and find an open circuit. Next, check out the resistance of the secondaries. Green is usually the 6.3 VAC filament, yellow is 5 VAC for the rectifier tube and red is high Voltage which is typically around 300 - 400 VAC. (Full wave rectifier, filter etc produces 150 to 250 VDC.)
From there, it just a matter of verifying that you have the correct Voltages.
Good Luck, Charlie k3ICH
Do you have a manual? If not, I think I have one that I would be happy to copy for you.
First, I would make absolutely sure that the transformer IS in fact bad. A Variac and some form of AC current measurement capability is a big help in that regard, but not a requirement. Since the radio appears dead, start by following the AC line cord plug with an Ohmeter. Normally, one lead goes to the transformer primary and the other is wired to the power switch, then to the transformer. You might get lucky and find an open circuit. Next, check out the resistance of the secondaries. Green is usually the 6.3 VAC filament, yellow is 5 VAC for the rectifier tube and red is high Voltage which is typically around 300 - 400 VAC. (Full wave rectifier, filter etc produces 150 to 250 VDC.)
From there, it just a matter of verifying that you have the correct Voltages.
Good Luck, Charlie k3ICH