View Full Version : IF transformer for healthkit gr-25


Phil
10-04-2019, 08:42 PM
Does anyone have a replacement for T203? Someone ran the core all the way to the bottom and I have had no success getting it to move.

bgadow
10-09-2019, 09:03 PM
Guessing you've tried using a little bit of heat or some lubricant? I'm thinking if you could come up with a cross reference-an actual part number from somewhere-you might be able to find one.

Phil
10-10-2019, 12:30 AM
Yes, I tried heat, oils, etc. That core wasn't about to go anywhere! I knew I didn't have anything in my parts stores since the only other set I have new enough to have a 45 mhz if is a philco safari.

I did find a core the same size in some of my parts for old amateur radio gear. I found a core in a healthkit Marauder transmitter. I used a core from the 10 meter section, thinking that since it needed to operate up to nearly 30 mhz it, hopefully wouldn't have excessive losses at 45 mhz. At least it would be closer than a 455 khz if transformer. I carefully broke up and removed the old core, inserted the replacement and gave it a try. It actually seems to work fine. So problem solved, at least with the if. Now if I can only get this thing to converge it should look very nice.

Electronic M
10-10-2019, 08:43 AM
The convergence diode packs are usually selenium and are moderately prone to failure...

Phil
10-10-2019, 03:33 PM
I was suspicious the diode block might be the problem. I replaced the selenium diodes in the horizontal AFC with BAT41s and they seem to be working well in that position. Would these also be satisfactory for the convergence diodes?

https://www.vishay.com/docs/85659/bat41.pdf

What do you recommend?

Thanks

kf4rca
10-11-2019, 09:30 AM
Why do you still need an IF strip? I converted my GR2000 to video input. Only needs a 2 transistor circuit to do this.
You will notice an improved picture as you are no longer bandwidth limited by the IF strip.
Of course, you will have to convert the audio to an input also.

Phil
10-11-2019, 02:04 PM
To each his own. If I were going to do that I would just buy a video monitor. I prefer my televisions to operate as designed.