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I hate seeing stuff like this when Dayton Hamfest is so close.

The best part is when they don’t realize it has a driver so they dump a 4 transistor amp into it. . Needless to say that didn’t end well. And I hate the filaments being in series.

The switch powers fan, LED and keying circuit. If switch bad or cold solder joint. That will stop everything

Just gonna say this. I posted elsewhere before. HG tolerance and quality are horrible. Your basically using the equivalent of Harbor Freight.

I believe the potentiometer in those Texas Stars are actually 1W I believe. I have a couple here somewhere. A 2W won’t fit. Keep it around 25-35w per pill max for carrier out of 500. Get a fan kit for that 500 or you’ll be frying bacon in no time.

Good deal. Glad it worked out.

I’ve ran into something similar to that before. I used aluminum tape and covered over the wires and the non moving center of fan. This stopped rf getting into the DC fan.

I’d have to sit down later and do some math. But why couldn’t you float the B- to a certain point and then use the B- to measure current like in a tube amp? Instead of trying to measure or read something on the B+? I’m asking, not saying you should. Then maybe you could use 100uA meter. Still...

I’d like that kit. Would be handy for hi pot testing some of the doorknobs and vacuum capacitors I have laying around. Wonder if he sells kit or has schematic.

Ok. Using the knock offs. Since not a true Toshiba, the capacitance values across the transformers and on input and output will more than likely be different. Will need retuned. Also since the amp is biased, I wonder how hard they are pulling for idle current?

The transistors you installed I take it are HG?

A new pair of tubes will cost you about $550. So make sure it works and tubes put out. Otherwise you could have to invest in it about what it was bought for.

These were matched by curve tracer, marked 63, I used Sencore TF46 and did check hfe. I went through 18 to find 6 that tested 41 & 42. Yes I used power device setting not small signal setting. I have built a few 2 device using the rd100fhh1 device. I like it. But still not really for a...

This last batch I bought. Was fixing a straight 6 pill/ transistor amplifier. Set up as 2 device sections. Had to match every capacitor ( all inputs within 1 of, all capacitors across transformers within 2pf, capacitors from collector to ground all matched within 1pf and same for outputs) so no...

Funny thing is they haven’t changed batch code in awhile. So theirs no way of knowing what you get. So every time you get a new batch, you have to build a pair on a tester and check the tune. Just to see if Tune is same or if more changes have been made.

The problem with the HG as well, at the factory they make changes but don’t tell anyone. On the regular HG 2879 there are at least 4 different tunes now in the last 2 years. The HG 2879C has at least 2 different tunes. Meaning what worked 6 months to a year ago won’t work now. Values are...

Did you put the same brand and type transistors in?

I guess the flange spec is like the center pin on the QC connectors. Close enough? Lol.

i figured I’d post this for informational purposes. The die or flange on these new DEI, HG and RFP 2879’s is larger than the old Toshiba flange. If you have to replace Toshiba with newer version, you will have to pull board and use a dremel to make transistor opening larger. I’ve had a lot...

Yes, I have a high resistance resistor in parallel with fuse holder. Can’t remember exact value. I believe it was about 15K ohm