Yes,,, Commercial Trades Institute,, Chicago IIRC,,, I wanted to learn AC/Refrigeration, for some reason,, and it was an A school in the Navy,,, I went to a different school, but the AC didn't work on my ship so there was plenty of gear to work on!!!! We finally got it up and running! I learn best OJT, or visual,,, reading comp, not so much!!
NRI was another well known school. Study at home deal. There were a few, Sprayberry being another.
Why do I remember this stuff????
Nothing like on the job training! That's how I learned the telecom trade, and test instrumentation (although we had classes in university on test instrumentation). Very effective.
Why do I remember this stuff????
Nothing like on the job training! That's how I learned the telecom trade, and test instrumentation (although we had classes in university on test instrumentation). Very effective.
That's what I told my buddy and my son,,, My sons an engineer and he keeps telling me the way I troubleshoot a problem,,, trial and error. is a proven engineering process... But I'm not, so OJT works for me,,, If I could stand behind you and watch your bench work for a day,,, I'd know more about this than I learned in this ten page thread!!!
I have a little Sprayberry VOM,,, I had to rebuild it, just because!!!!!
I have a little Sprayberry VOM,,, I had to rebuild it, just because!!!!!
The problem with watching a technician, especially a good one, is that a lot gets processed in their head quickly. They will take steps based on observations and things in their heads. So watching a good tech means you will miss a lot of important stuff.
I trained techs for years. Slowing down and showing each step is painful and it is easy to work in your head - it is very difficult to slow down and show each step you run through in your head. The problem with electronics is that you can't see the electricity. You only interpret it with instrumentation and what that shows is up to the skill of the operator. The mental picture of the circuit is combined with observations in your head and that can lead to intuitive leaps that do not make sense to an observer who isn't trained well.
I trained techs for years. Slowing down and showing each step is painful and it is easy to work in your head - it is very difficult to slow down and show each step you run through in your head. The problem with electronics is that you can't see the electricity. You only interpret it with instrumentation and what that shows is up to the skill of the operator. The mental picture of the circuit is combined with observations in your head and that can lead to intuitive leaps that do not make sense to an observer who isn't trained well.
I understand that, ,, but I was building ckts when I was five,,, always watched my uncles , never had any formal training except one year of a two year vo-tech course in high school, and a summer of working for a local electrician before I got drafted.. I told the guys that worked for me to watch what I do,,, and my son and my buddy got it,,, a couple other guys just couldn't,, but could do what ya told them,,,
My buddy is head tech at a power plant and my son is senior project engineer for a big mechanical contractor,,, They always tell me they both got the jobs because of what they learned from me,,,
Maybe I wouldn't learn it from watching you, but I would certainly pick up something, and then research and find out more about it!!
Looking fwd to getting the proper readings from this receiver, so I can repair the MPX and get it aligned,,, seems I'm just a couple tools short for now tho..
My buddy is head tech at a power plant and my son is senior project engineer for a big mechanical contractor,,, They always tell me they both got the jobs because of what they learned from me,,,
Maybe I wouldn't learn it from watching you, but I would certainly pick up something, and then research and find out more about it!!
Looking fwd to getting the proper readings from this receiver, so I can repair the MPX and get it aligned,,, seems I'm just a couple tools short for now tho..
lol!
Hi John,
Yes, you would pick some things up for sure. I would take the time to explain steps and things to watch out for. I've been trained to train! lol!
Common sense does go a long way. I try and teach that, but some folks just are not capable. The basics for all these jobs is similar, so I'm not surprised they found what they learned from you helpful.
Yes, you're almost there and you have a friend with really nice equipment.
Hi John,
Yes, you would pick some things up for sure. I would take the time to explain steps and things to watch out for. I've been trained to train! lol!
Common sense does go a long way. I try and teach that, but some folks just are not capable. The basics for all these jobs is similar, so I'm not surprised they found what they learned from you helpful.
Yes, you're almost there and you have a friend with really nice equipment.
I can see you are a teacher! Common sense ain't common!!
My friend lost the signal in this Scott tuner (the separate amp he rebuilt works fine),, He is able to take the obsolete gear from the "school" at the power plant where he works, as they just trash it when something better comes along!!! I told him a while ago to grab a signal tracer if one comes available, and showed him my Eico 147 that I rebuilt,,, He found one and rebuilt it, and found where the signal stopped... So now he's into his tuner... Plan is to align it to learn,,, and then my Sansui,,,, So I'm hoping I can get FM MPX back when he's ready!!!!
I used my VTVM to "adjust " a Simpson DMM I had that seemed to always read low, on all ranges,,, I found it has one pot in it so I connected it to a SS power supply, and the VTVM and turned the pot,,, all the DCV ranges are back to normal and held on 425VDC Vp all afternoon (big tube amp I just started to rebuild and modify) Gotta try the low V now, and see if the Sui readings I took with his Fluke match the Simpson...
See, I'm trying to get this sorted out!!!!
Here's pics of that amp,,, first two are as found,,, third is as it is now, it's up and running with an added tone stack stage, but still a work in progress!!! I got this the same time as the Sui,, and it became a diversion while waiting for Sui parts, so it fits in this thread!!!
As always,, I appreciate your time, help and conversation!!!
My friend lost the signal in this Scott tuner (the separate amp he rebuilt works fine),, He is able to take the obsolete gear from the "school" at the power plant where he works, as they just trash it when something better comes along!!! I told him a while ago to grab a signal tracer if one comes available, and showed him my Eico 147 that I rebuilt,,, He found one and rebuilt it, and found where the signal stopped... So now he's into his tuner... Plan is to align it to learn,,, and then my Sansui,,,, So I'm hoping I can get FM MPX back when he's ready!!!!
I used my VTVM to "adjust " a Simpson DMM I had that seemed to always read low, on all ranges,,, I found it has one pot in it so I connected it to a SS power supply, and the VTVM and turned the pot,,, all the DCV ranges are back to normal and held on 425VDC Vp all afternoon (big tube amp I just started to rebuild and modify) Gotta try the low V now, and see if the Sui readings I took with his Fluke match the Simpson...
See, I'm trying to get this sorted out!!!!
Here's pics of that amp,,, first two are as found,,, third is as it is now, it's up and running with an added tone stack stage, but still a work in progress!!! I got this the same time as the Sui,, and it became a diversion while waiting for Sui parts, so it fits in this thread!!!
As always,, I appreciate your time, help and conversation!!!
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Hey!
Nice job! I rebuild old gear when I have a chance. I like what you did with the chassis. It looks like a nice PA amp.
Nice job! I rebuild old gear when I have a chance. I like what you did with the chassis. It looks like a nice PA amp.
Thanks a cool diversion!!!
I met the guy that had that amp in his damp basement for over 30 years,,, he gave it to a hamfest buddy that thought I would do something with it!!! I got its history!!
I met the guy that had that amp in his damp basement for over 30 years,,, he gave it to a hamfest buddy that thought I would do something with it!!! I got its history!!
IT-18 arrived,,, looks to be in good shape,,, other than battery was left in it, and corroded the holder,,, I wire wheeled it clean,
Got this far on Adjustments page,,, Beta Cal,, Full CCW,,, however pot doesn't stop in either direction,,, so I cant index "full CCW"...
Got this far on Adjustments page,,, Beta Cal,, Full CCW,,, however pot doesn't stop in either direction,,, so I cant index "full CCW"...
I had to buy a new holder for one. I got it from Digikey as I recall, maybe a Keystone part. Single "D" cell holder, metal. Fit the old holes exactly.
I would clean the switches and check the diodes to make sure they aren't shorted. Then of course there are the switch contacts as well. Use a zero residue cleaner, you may have to use WD-40 or something first (shutter), just make sure you follow that right away with a zero residue cleaner. Once you get it working properly, I would replace the battery holder but it might be okay for now. I haven't looked, but some contacts are plated and once you get to base metal the connection isn't nearly as good.
I would clean the switches and check the diodes to make sure they aren't shorted. Then of course there are the switch contacts as well. Use a zero residue cleaner, you may have to use WD-40 or something first (shutter), just make sure you follow that right away with a zero residue cleaner. Once you get it working properly, I would replace the battery holder but it might be okay for now. I haven't looked, but some contacts are plated and once you get to base metal the connection isn't nearly as good.
Makes sense,,, as I didn't buy it,,, my buddy asked me to try it out and see if its as advertised,,, Everything else is like new,,, just a concern with the instructions, opposed to operation of the Beta cal pot,,, Where is full CCW if it never stops!!!??
Battery box has one corroded hold clip,,, contacts are brass rivets and very clean...
Now to learn how it works..
Battery box has one corroded hold clip,,, contacts are brass rivets and very clean...
Now to learn how it works..
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That control is a multi-turn control. It does eventually stop.
Clean the trimmer on the switch. Verify the resistors have not drifted, their precision resistors were pretty good.
As simple as this instrument is, it is accurate and a real boon to the test bench. One of the very best things I have ever bought! I have the more expensive units from Heathkit and others (B&K also), but the IT-18 is the very best for what we do on the bench as far as determining good or bad.
Clean the trimmer on the switch. Verify the resistors have not drifted, their precision resistors were pretty good.
As simple as this instrument is, it is accurate and a real boon to the test bench. One of the very best things I have ever bought! I have the more expensive units from Heathkit and others (B&K also), but the IT-18 is the very best for what we do on the bench as far as determining good or bad.
OK,,, I'll clean it and set it up as the manual says.. Didnt think it was a multi turns pot... Good info..
Well, just let me know what you find.
The calibration depends greatly on that 180R resistor and battery voltage. My strong suggestion is to order a 180 ohm 1% 0.6W metal film resistor next time you order parts and use that. The calibration will change a bit with battery voltage. I've been toying with the idea of making a 1.5 VDC regulated supply for it. So check the cal when you replace the battery and at intervals simply so your measurements agree over time.
If you only check to see if a transistor is good, calibrate it properly and just check every now and again.
The calibration depends greatly on that 180R resistor and battery voltage. My strong suggestion is to order a 180 ohm 1% 0.6W metal film resistor next time you order parts and use that. The calibration will change a bit with battery voltage. I've been toying with the idea of making a 1.5 VDC regulated supply for it. So check the cal when you replace the battery and at intervals simply so your measurements agree over time.
If you only check to see if a transistor is good, calibrate it properly and just check every now and again.
I just cleaned teh switches,,, The beta cal pot never stops turning,,, shaft seems to move in and out of the case about 1/8" I need to take it out of the ckt and check it with a ohm meter,,to see if it registers... same with diode,, cant get a good reading with it in the ckt
Darn it!
The cal pot has been broken. I took mine apart to look at it. I think a gorilla hit the end stop and forced it.
See if the back is tight to the front plate, if not press together and test.
Option, repair it. The tabs bend (carefully and not all the way!) so the rear comes off. The ball bearings form a reduction assembly, so when the back comes off pay very careful attention as to what goes where and what comes out. Take pictures!!! Somewhere the turning part to the wafer that holds the sliding contact has been broken or bent. You may be able to clean the grease off, straighten or glue (epoxy) that part together. Let it fully cure, then use fresh grease and reassemble. Cleaning the wiper wouldn't hurt right now. Test before you bend the fingers back in place. If it works, bend the tabs gently, if one breaks you'll have to file, then solder it together. It's work, but the repair should last.
Repair failed? Okay, it's a 500 meg control (mine measured 510 K approx.), 10 or 15 turn. The 15 turn will be easier to use. Half flat shaft I believe, 1/2 watt. They aren't cheap controls. Digikey #987-1626-ND at about $290 Canadian (stupid - so no!) Look further ... Hmmm, the answer would probably be surplus or a single turn with 10 to 20 turn indicator knob. No way you can use it with a single turn!
The most intelligent option if you can't repair it is to buy another meter. If it's in rough shape - fantastic as long as the shaft isn't bent. You could use the battery holder anyway. Nothing wrong with a spare meter, but if broken you should be able to get it dirt cheap!
The cal pot has been broken. I took mine apart to look at it. I think a gorilla hit the end stop and forced it.
See if the back is tight to the front plate, if not press together and test.
Option, repair it. The tabs bend (carefully and not all the way!) so the rear comes off. The ball bearings form a reduction assembly, so when the back comes off pay very careful attention as to what goes where and what comes out. Take pictures!!! Somewhere the turning part to the wafer that holds the sliding contact has been broken or bent. You may be able to clean the grease off, straighten or glue (epoxy) that part together. Let it fully cure, then use fresh grease and reassemble. Cleaning the wiper wouldn't hurt right now. Test before you bend the fingers back in place. If it works, bend the tabs gently, if one breaks you'll have to file, then solder it together. It's work, but the repair should last.
Repair failed? Okay, it's a 500 meg control (mine measured 510 K approx.), 10 or 15 turn. The 15 turn will be easier to use. Half flat shaft I believe, 1/2 watt. They aren't cheap controls. Digikey #987-1626-ND at about $290 Canadian (stupid - so no!) Look further ... Hmmm, the answer would probably be surplus or a single turn with 10 to 20 turn indicator knob. No way you can use it with a single turn!
The most intelligent option if you can't repair it is to buy another meter. If it's in rough shape - fantastic as long as the shaft isn't bent. You could use the battery holder anyway. Nothing wrong with a spare meter, but if broken you should be able to get it dirt cheap!
Thanks for confirming,, even tho its bad news,,, this is why I will never use ebay/amazon or any other shipper,,,
I sent your explanation message to my buddy, in hopes he gets a refund, and I am willing to try to repair it if he can....otherwise I told him to send it back!!!
I will post results here,,,
Thanks again for the info,,,
I sent your explanation message to my buddy, in hopes he gets a refund, and I am willing to try to repair it if he can....otherwise I told him to send it back!!!
I will post results here,,,
Thanks again for the info,,,
Hi John,
I would take a partial refund and keep it since the cosmetics are so good. Then buy a scrapper for parts. Even if you were stuck with that one, cosmetics are everything (and the meter especially). Understand they were over $100 new, convert to today's funds for a rough value.
Grab another. They are cheap as heck and extremely useful meters.
I would take a partial refund and keep it since the cosmetics are so good. Then buy a scrapper for parts. Even if you were stuck with that one, cosmetics are everything (and the meter especially). Understand they were over $100 new, convert to today's funds for a rough value.
Grab another. They are cheap as heck and extremely useful meters.
I just tried it again as the buyer wanted pics to deal with the seller,, altho I told him the damage was internal..
As received, the pot shaft would move in and out by at least an 1/8th inch.... and would never arrive at a stop,,, how ever,, I pushed the shaft in and it seems to have clicked in place, and in watching the white wafer from the back,, the wafer does seem to stop moving after 15 or so turns,,, but knob/shaft never stop turning, so there will be no way to index the wafer with the knob in use... It seems to be gear drive with some kind of stop that is broken/dislodged?
I connected the pot, in ckt to my Fluke ohmeter and it starts at 0 and wafer stops at 505K,,, but it tracks erratically at lower ranges starting around 20K ~100k more or less, but knob/shaft continually spins,,, Is it supposed to? If so I maybe I can use it out of the case to see where the wafer is?
Just adding some info as you can't actually see it,,, Maybe it can be saved?
Thanks
As received, the pot shaft would move in and out by at least an 1/8th inch.... and would never arrive at a stop,,, how ever,, I pushed the shaft in and it seems to have clicked in place, and in watching the white wafer from the back,, the wafer does seem to stop moving after 15 or so turns,,, but knob/shaft never stop turning, so there will be no way to index the wafer with the knob in use... It seems to be gear drive with some kind of stop that is broken/dislodged?
I connected the pot, in ckt to my Fluke ohmeter and it starts at 0 and wafer stops at 505K,,, but it tracks erratically at lower ranges starting around 20K ~100k more or less, but knob/shaft continually spins,,, Is it supposed to? If so I maybe I can use it out of the case to see where the wafer is?
Just adding some info as you can't actually see it,,, Maybe it can be saved?
Thanks