https://youtu.be/Gn_-z-noVGs
And now I've finally got a minute to post some pics... I went and did it just to prove I wasn't just blowing smoke up your arse.
As always... the fabricobbling comes easy; its documenting shit that makes it take 3 times as long.
For now I'm just going to leave this here with the descriptions on the photos... it's late & I'm tired, and I have the kids all over me like ferrets on crack until Monday. Oh, and a road trip to Louisiana in there somewhere I need to rest up for...That's some fab fabbing, mnem. Added to POI.
That's a lot of damn caps... a few were leaking, most check okay, a few a bit week. This is the Boeschert power supply out of my second 53310a, caps on order.
You can see where the caps were leaking, but the board cleaned up nicely (not in this pic).
That's a lot of damn caps... a few were leaking, most check okay, a few a bit week. This is the Boeschert power supply out of my second 53310a, caps on order.
You can see where the caps were leaking, but the board cleaned up nicely (not in this pic).
Woahh good job
Are you using one of those desoldering gun ? Two irons ? Or just a lot of patience ?
That's a lot of damn caps... a few were leaking, most check okay, a few a bit week. This is the Boeschert power supply out of my second 53310a, caps on order.
You can see where the caps were leaking, but the board cleaned up nicely (not in this pic).
Woahh good job
Are you using one of those desoldering gun ? Two irons ? Or just a lot of patience ?
Just found a very cool feature on my Racal 9915 counter. On the A input (40-520MHz) it has an AGC and a corresponding AGC output on the back of the unit.
So I was just building a frequency multiplier as I need a 30MHz source and only have 25MHz AWG (fail!). Easy enough - just shove a grounded emitter amp with a 30MHz tank on it (600nH + 22-ish pF) into the front of your 10MHz source (Rigol AWG). Well turns out if you plonk your DMM (or voltmeter) across the two AGC terminals on the back it'll allow you to get a rough signal strength indication. Pop it on the multiplier and tune for max value and job done! Very handy.
The find of the evening came while we were sorting through boxes of printer switches, random power cords, etc:
Damn if it didn't have the AC adapter still attached and lit up when I hit the power switch. Do you want it? I was just going to throw it in with a bunch of computers going to ecycle. I allowed as I would find it useful and set it aside.
An HP45! Yes, the very same model my vo-tech instructor used to flaunt while checking our (slide-rule-calculated) quiz and test answers. I haven't seen one in more than forty years. It cost 395USD in 1973 and was the first calculator to have a shift key
Happily, the battery (last changed in 1986) didn't leak. Tomorrow I will figure out how to build a replacement battery pack and put it back into daily use.
Made good progress on running the 7904A. This is a hell of a scope. On the off chance does anyone know how to "zoom in" properly on a rising edge for a rise time measurement? On my 2465B I don't really have to think about it, but on the 7904A the edges always end up off the screen.
Looks like the 7A26 needs some compensation adjustments, especially channel 1 (see pics). Unfortunately I don't yet have all the specified things for the cal procedure from the 7A26 manual.
Made good progress on running the 7904A. This is a hell of a scope. On the off chance does anyone know how to "zoom in" properly on a rising edge for a rise time measurement? On my 2465B I don't really have to think about it, but on the 7904A the edges always end up off the screen.
Looks like the 7A26 needs some compensation adjustments, especially channel 1 (see pics). Unfortunately I don't yet have all the specified things for the cal procedure from the 7A26 manual.
Go to the 5 mV setting first and check the trace. If it's peaking like that then the issue is NOT the compensation adjustments in the switch deck but the adjustments in the pre-amp section itself. The 5mV setting goes directly into the pre-amp and bypasses the switch deck compensation. If that trace is OK then proceed with the adjustments at the other switch sections. And be aware there will be interaction between switch settings. And typically on the attenuators a peak like that is corrected with the bottom adjustment. The top adjustment generally affects the flat top but again there is interaction. Work slowly and carefully and with each adjustment go back and check the other settings. Trust me. I've done a few including the 7A26. They can be a real PITA but worth the trouble.
Edit...also...in my experience you don't need the additional "compensator" and some the other expensive equipment to do a decent compensation. Just a fast rise time and high quality 1Khz square wave will get you there. And obviously it needs to have adjustable gain to do each deck.
That's a lot of damn caps... a few were leaking, most check okay, a few a bit week. This is the Boeschert power supply out of my second 53310a, caps on order.
You can see where the caps were leaking, but the board cleaned up nicely (not in this pic).
Woahh good job
Are you using one of those desoldering gun ? Two irons ? Or just a lot of patience ?
I applied a the EEVblog and .edu discounts on tequipment to buy me a Hakko handheld desoldering gun last year and it is the best thing ever. I can imagine one of the bigger units with a separate vacuum unit is even better. I don't need it often, but when I do, it beats wick hands down.
Isn't that overshoot what we call Step Response ?
There should be instruction of how to trim it out against a suitably fast edge source.
RTFM.
The find of the evening came while we were sorting through boxes of printer switches, random power cords, etc:
Damn if it didn't have the AC adapter still attached and lit up when I hit the power switch. Do you want it? I was just going to throw it in with a bunch of computers going to ecycle. I allowed as I would find it useful and set it aside.
An HP45! Yes, the very same model my vo-tech instructor used to flaunt while checking our (slide-rule-calculated) quiz and test answers. I haven't seen one in more than forty years. It cost 395USD in 1973 and was the first calculator to have a shift key
Happily, the battery (last changed in 1986) didn't leak. Tomorrow I will figure out how to build a replacement battery pack and put it back into daily use.
Calculator collecting is just as addicting as test equipment. See http://web.jlw.com/test/calc.html
While I no longer have an HP-45, I do have an HP-34C and an HP-97 from the next generation.
Isn't that overshoot what we call Step Response ?
There should be instruction of how to trim it out against a suitably fast edge source.
RTFM.
If it is "step response" Tek doesn't call it that. He just demonstrated with his last post that the pre-amp section is OK and should not require any adjustments. The issue is the attenuator adjustments in the switch deck. Yes, the manual tells you how to do it but I'm warning him that there is ALOT of interaction that the manual doesn't mention and can frustrate a "first timer"
Isn't that overshoot what we call Step Response ?
There should be instruction of how to trim it out against a suitably fast edge source.
RTFM.
If it is "step response" Tek doesn't call it that. He just demonstrated with his last post that the pre-amp section is OK and should not require any adjustments. The issue is the attenuator adjustments in the switch deck. Yes, the manual tells you how to do it but I'm warning him that there is ALOT of interaction that the manual doesn't mention and can frustrate a "first timer"OK yeah, there's no overshoot on some V/div ranges which as you say points to individual attenuation adjustments.
Could just one be possibly damaged and affect a few others ?
Isn't that overshoot what we call Step Response ?
There should be instruction of how to trim it out against a suitably fast edge source.
RTFM.
If it is "step response" Tek doesn't call it that. He just demonstrated with his last post that the pre-amp section is OK and should not require any adjustments. The issue is the attenuator adjustments in the switch deck. Yes, the manual tells you how to do it but I'm warning him that there is ALOT of interaction that the manual doesn't mention and can frustrate a "first timer"OK yeah, there's no overshoot on some V/div ranges which as you say points to individual attenuation adjustments.
Could just one be possibly damaged and affect a few others ?
Yes, there is some interaction between ranges which can catch you off guard. If you make an adjustment you basically have to go back and check everything again. It can be quite tricky.
Isn't that overshoot what we call Step Response ?
There should be instruction of how to trim it out against a suitably fast edge source.
RTFM.
If it is "step response" Tek doesn't call it that. He just demonstrated with his last post that the pre-amp section is OK and should not require any adjustments. The issue is the attenuator adjustments in the switch deck. Yes, the manual tells you how to do it but I'm warning him that there is ALOT of interaction that the manual doesn't mention and can frustrate a "first timer"OK yeah, there's no overshoot on some V/div ranges which as you say points to individual attenuation adjustments.
Could just one be possibly damaged and affect a few others ?
Yes, there is some interaction between ranges which can catch you off guard. If you make an adjustment you basically have to go back and check everything again. It can be quite tricky.Would you ever suspect one setting to have been damaged maybe with an over-voltage event ?
If that was the case would you check to see which setting is most effected and then check the attenuator components for accuracy before attempting to trim it out ?
Or would such an event more likely damage something else in the inputs ?