May have commented on this before, but part of my training in electronics at the start of my career in the Army was to remove all watches, rings, and other metal, including dog tags, before working on electronics. We did work around both high voltages, and low voltage high current supplies. If you've ever seen the results of someone getting a wedding or other ring shorted to a high current 5 V supply you'll be convinced that removal is a good practice ;-)
I for one would like to thank the trained technicians at both the army and AF repair depots for equipping my lab with dirt cheap test equipment via government auctions. I always look for their red tags that say "Not Repairable." My favorite was the Fluke bench multimeter where they replaced a defective IC, but installed the new IC backwards. Thanks guys!
@@johnwest7993 While I was in, 1976-1980, all the test equipment was sent off to a commercial outfit for regular calibration and repair as required. Not maintained by Army personnel. We just worked on the communications equipment using said test equipment. But +1 to low cost surplus test equipment.
Things I remember... Some of the cans have 5 volt regulators inside. Surprise! The separate grounds were an attempt to reduce noise from the digital getting into the analog. Beware the ugly sidebands. Yeah, most of the schematics are a suggestion. Good luck! 73 es GB W3IHM
Two things - there may be a diagram of the coax connection on the underside of the top cover that you removed in the first video. Also, if there is a shorted +/-18V the most likely culprit is one or more tantalum capacitors that are sprinkled throughout the modules. You need tantalums for their frequency bandwidth as replacements or a parallel electrolytic and mlcc as things get noisy. You can unplug modules by removing a screw or screws from the underside. The screw on top just holds the cover of the module. I have two 3001s that I got working after many electrolytic and tantalum cap replacements. BTW, the LEDs on some modules come on if the particular PLL is out of lock. Also the red button on the module next to the attenualtor is an overload test or reset (can't remember which) on the circuit breaker module.
Weird that lack of ground in half the psu😮, beautiful instrument, they are impossible to get here, prohibitely expensive, i was lucky to find a motorola 2600 mostly working, good tube!, No modulation though, but no biggie, i gotta do a video about that one, i would love to see you working on one of those!
It's hard to catch, but if you look at the top and bottom of the PCBs there is no evidence of any connection to the "ground island" which includes the replaced 100uF capacitors. Goes to the round IC and a passive below, one pin on the connector (and only 1 ground pin, the rest are voltages), the 100uFs and their bleeders, jumpers up into around one of the regulators. But no possibility of grounding through their tabs since it doesn't run to the centre terminal of any. No "empty" pads for a jumper. Looks like a complete oversight that required a bodge wire in production. EDIT: would love a full view of the front and back of these while troubleshooting. Even if you figured it out, it's fun for us to exercise our skills.
The suspense of how many repair sessions is a realistic addition. I've got a few boxes of in- progress projects!
I enjoy troubleshooting videos. Keep them coming!
Great video! I would never consider a broken ground plane!
May have commented on this before, but part of my training in electronics at the start of my career in the Army was to remove all watches, rings, and other metal, including dog tags, before working on electronics. We did work around both high voltages, and low voltage high current supplies. If you've ever seen the results of someone getting a wedding or other ring shorted to a high current 5 V supply you'll be convinced that removal is a good practice ;-)
I respect the fact you have the experience training but please bear in mind, so do we. :)
Not to mention high power, UHF RF, on my watch, Auch, I remember that was a nasty burn from the 500 MHz 1KW PA😢
@@leandrolaporta2196 Oh the smell of Bacon Butties !! Lol :)
I for one would like to thank the trained technicians at both the army and AF repair depots for equipping my lab with dirt cheap test equipment via government auctions. I always look for their red tags that say "Not Repairable." My favorite was the Fluke bench multimeter where they replaced a defective IC, but installed the new IC backwards. Thanks guys!
@@johnwest7993 While I was in, 1976-1980, all the test equipment was sent off to a commercial outfit for regular calibration and repair as required. Not maintained by Army personnel. We just worked on the communications equipment using said test equipment. But +1 to low cost surplus test equipment.
Things I remember... Some of the cans have 5 volt regulators inside. Surprise! The separate grounds were an attempt to reduce noise from the digital getting into the analog. Beware the ugly sidebands. Yeah, most of the schematics are a suggestion. Good luck! 73 es GB W3IHM
You have your handy little SEQURE rechargeable soldering iron. It might come in handy for fixing this Wavetek. 🙂👍
no battery in that
@@IMSAIGuy Oh right. It runs off USB.
The LM395 is a high-gain transistor replacement with internal protection.
I used to just use a towel until that one day that one of the many cutoffs poke though the towel and everything got interesting.
enjoyed this, thanks!
wow
still labeled 'em QXXX tho. 😀
LM395 is a precision transistor IC. Marking it "Q" is probably okay.
Two things - there may be a diagram of the coax connection on the underside of the top cover that you removed in the first video. Also, if there is a shorted +/-18V the most likely culprit is one or more tantalum capacitors that are sprinkled throughout the modules. You need tantalums for their frequency bandwidth as replacements or a parallel electrolytic and mlcc as things get noisy. You can unplug modules by removing a screw or screws from the underside. The screw on top just holds the cover of the module. I have two 3001s that I got working after many electrolytic and tantalum cap replacements. BTW, the LEDs on some modules come on if the particular PLL is out of lock. Also the red button on the module next to the attenualtor is an overload test or reset (can't remember which) on the circuit breaker module.
Weird that lack of ground in half the psu😮, beautiful instrument, they are impossible to get here, prohibitely expensive, i was lucky to find a motorola 2600 mostly working, good tube!, No modulation though, but no biggie, i gotta do a video about that one, i would love to see you working on one of those!
LM395 is an IC that acts like a Darlington transistor, but adds thermal and overload protection circuits.
Kinda. It uses a pnp input so that it has only one diode drop for Vbe despite being a darlington.
I am not familiar with that particular instrument but wonder if the missing ground is provided by the wiring in the output connector??
It's hard to catch, but if you look at the top and bottom of the PCBs there is no evidence of any connection to the "ground island" which includes the replaced 100uF capacitors. Goes to the round IC and a passive below, one pin on the connector (and only 1 ground pin, the rest are voltages), the 100uFs and their bleeders, jumpers up into around one of the regulators. But no possibility of grounding through their tabs since it doesn't run to the centre terminal of any. No "empty" pads for a jumper. Looks like a complete oversight that required a bodge wire in production.
EDIT: would love a full view of the front and back of these while troubleshooting. Even if you figured it out, it's fun for us to exercise our skills.
Pin 9 is a ground from the main unit, been confused myself.