Heathkit Repair - Visual Aural Signal Tracer IT-12 - 1 of 2
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- čas přidán 24. 12. 2017
- This is more of an express video of a Heathkit IT-12 signal tracer restoration since it closely matches that of the T4. The big difference in this series is that much more attention is payed to the DC circuit and rectifier to determine if further noice reduction can be attained by replacing the single diode selenium rectifier with more modern upgrades
#heathkit #testequipment #restoration - Věda a technologie
I put in a full rectifier and appropriate resistor to get 138V. I also removed C7-C.
Full rectifier is the way to go.
Just a suggestion, when dealing with power supply ripple, you can also try to add another capacitor to what's already there but make it smaller in value and if possible as low of ESR as well. The smaller value capacitor is better at higher frequencies and the larger ones take up anything that needs bulk current! I personally first saw this technique somewhere in CZcams and have been doing it ever since with excellent results... If you had the room and didn't mind changing things or even if it's a new build, you can just use lots of smaller value capacitors instead of less larger ones and you will have dead flat DC output...
Thats a good tip, thanks for sharing.
@@retrotechandelectronics You are welcome, when you watch enough videos about capacitors you start to develop an understanding of how they work. There's a lot more to them than most people realize! When it comes to amplification power supplies you usually see large bulk capacitors but then when you look at switch mode power supplies you see that they use much smaller capacitors, I personally think that it's a good idea to use both when it comes to obtaining a clean and flat DC output..
They did that very thing in the Heathkit SG-8!
My electrolytic was good also. I brought all three sections up slowly watching the current. The 50uf caps ended up below 400ua, the 20uf below 40ua. Amazing for 40+ year old caps. I say if they last that long there pretty good. Mine has a ss rectifier. Had a wire not soldered also.
Sometimes you bring em' up and the internal heat over time pushes out the moisture, causing temporary improvement, but it comes back. Ive opened these cans up in my videos, they simply rot over time
Can you explain the process to restore the hammered finish on the exterior of these Heathktit chassis cases.. You mentioned its easy to repair but I didn't actually understand what can be done... I have a couple of these Heathkits that require attention! Thx, Ben
Thank you for a most instructive video. Would you show how you gut & re-stuff can capacitors please? I have done this for valve Radios but it's a clumsy process at best. I'm always looking for ways to improve my work.Thank you.
I believe my IT-4 repair video goes into detail on restuffing the can capacitor
I have the same the triple electrolytic capacitor was ok also ! If i remember well they was a death cap on the ac line also !
'OK' is relative on a device that is supposed to have as little internal hum as possible.
This is just a question...I have seen you check a few tubes with your tube checker...and to me..it seems that it goes all the way to the right to fast..and goes to far...is it ok???? Some times it pegs out to the right at over 100%...and I mean not just past 100% but WAY past 100%.
The older century tester has since been replaced by the Hickok 6000. While the century has been repaired there is still some work to be done on it im sure.
What is the difference between theT4 and the IT-12? Which model was introduced first? Thank you and have a most awesome evening!
I believe the T4 was first, Denoted by the gray case, though beyond cosmetic, functionally identical.
Very kewl, thank you for the extremely expeditious reply.
I always buy a new CAN from Radio Daze. I won't take the time to stuff!
I have one that's pretty beat up and the cords are cut on it front and back if anybody's interested in owning it reply with your email address and I'll see if I can send you some pictures
how beat up?
@@retrotechandelectronics the on off knob is the switch labeled noise is loose and broken the front cover is pushed out at the top and pushed in at the bottom all the red and black hookups are bent but there Magic Eye appears to be intact the handle is not broken the wires have been cut at the grommets front and back the paint on the back of the machine appears to be silver or Chrome and is peeling away
I just ended up with one of these in a load of junk someone gave me. I don't think it is really my cup of tea. I'm not a tube guy. The one I got looks like it's been through a war. So no great loss if I don't try to fix it up. Even the handle is broken in half.
At least you got it for free, some folks get horror stories on ebay....
Yeah I just got a small horde of junk. A couple winners and a couple meh items. You can see the IT-12 on the right side in this picture i.imgur.com/aef0GZE.jpg Even that meter came in the haul. I recapped that EICO batter eliminator charger and it works. The Superior Electric VOLTBOX just worked right off the hop. So it was a big win.
Thats rough... But the VARIAC on the left looks like a score. Thats a 200$ item!
I'm happy to have the Variac. I bought a smaller bare one at a flea market a while back but it is only 3 amps so of limited use. I brought that IT-12 up on this new one to me and it did not blow up. One tube glowed and the unit made its characteristic hum, but the magic eye never came on. So I don't see a point in trying to fix it.
3 Amp variac , thats 360 watts. Substantial for most applications including an ST70 amplifier if youre carefull
If you ever decide to sell one of your signal tracers let me no ,because of the crap they sell on ebay sometimes,you take risk ,half the time the people selling vintage gear dont even no what they are selling .and because it's old they think it's made of gold.
eBay is overpriced but convenient. Unless one lands in your lap or you find one at a ham swap meet eBay is really the only game in town.
appalling audio, why sit in the garden and talk when you should be in the shack. video content good