Thanks Tautech, will go and source a more powerful bulb... even if that means I need to order it online, since local shop won't do higher than the 77W I found.
I am back from the bench... VICTORY !!!
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/xcheesy.gif.pagespeed.ic.KPzuH4J-TG.png)
The light bulb tester made me chase red herrings and worry needlessly : my repair of the regulator, somehow, despite the numerous components that I replaced... worked first time ! Thanks to all who helped me through this !
My first decently involved repair... sure was more involved than me replacing a tactile switch in my 10 bucks alarm clock !
![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif.pagespeed.ce._hfWAz_QHO.gif)
Was my first time working on a real world SMPS, so I learned a lot along the way, thank you every one.
I am so glad my little 2232 is back to life, it's my main scope and I love it to bits.
I adjusted the trimmer in the inverter section, following the calibration procedure in the service manual. They take the -8,6V rail as their reference, so I set that spot on to the required 8,60V, and all the other rails were spot on too... except for the +/- 5V rails which were way off, but I didn't care since I assumed they would comply once I would plug the digital board back in. Sure it helped... but then all the other rails moved in unison ! They dropped enough to be out of spec ! So, I readjusted the -8.6V again to be spot on 8,60V. and all was good again. all the rails are within spec now... though the 5V rails are on the high side : +5,17 and -5.25V (max allowed). The 8.6V rail is also on the verge : 8,64V for an allowed maximum of... 8,64V...
So I am half-temped to drop the -8,6Volt reference just a tad (-8,56V minimum allowed) so as to bring the +8,6 and 5V rails a little bit on the safer side of things... what do you think ??
So, the scope it working again, nice... but after a quick test, I see there as still some minor issues I would like to fix, at least try to.... if it's not too involved.
1) Probe compensation signal is inverted : shows up as 0 to minus 0.5V instead of +0.5V. Had this problem when I tested the scope without the digital board, while powering the inverted directly from the bench power supply. Well now that the digital board and everything is put back together... the problem is still there sadly !
![Angry >:(](https://www.eevblog.com/forum/Smileys/default/xangry.gif.pagespeed.ic.0w4zhwjvDw.png)
I tried on both channels, and they behave the same. So I hooked the probe to the compensation signal from another scope, my old Tek 5111 (100Hz 400mV signal), and the 2232 displayed it just fine ! What a relief ! So the scope itself is fine... it's just the probe compensation signal itself that's upside down... only a minor annoyance you might say, as this doesn't keep one from compensation his probes.. but still, it's not normal so if I can fix it... why not.
If it were my 5111 it would be easy. If it were my TDS 310 or TDS544A it would be easy too... the signal is generated locally on the front panel assembly, which easily pops out to let you work on it... but the accessibility of the front panel on th e2232 looks a nightmare... will check the service manual and schematics.
2) When in digital/store mode, I witness too issues : the trace is not centered anymore : it is shifter down a little bit, by roughly a small division. Also, when I use the vertical position knob to readjust it, the traces moves rather jerkily. See video clip...
One would say that the pot just needs cleaning, expect that this very same pot works like a charm in analog mode...
https://youtu.be/ug77tJohVSA3) Fan is noisy... after 30 years I guess it's to be expected eh. Makes both a low pitched rumble as well as a high pitched noise that drive my ears a little mad to be honest. the latter noise does not come from the SMPS... my new regulator transformer is absolutely silent, the other transformers too. Any advice on a good replacement (brand and model ) ? The 'PC' gamer nerds, IIRC, are well versed in this domain... but IIRC desktop computers use only 80mm and 120mm fans right ? So this crowd won't be much help for the Tek, as I measured the old fan and it's a smaller, 60mm unit ! Bummer. Still, they could advise on brands, I presume.
Specs are as follows :
Brand : " Sunon "
Model " MD 1206 PTS1 "
12V DC, 1.5 Watt
60x60x25,4mm.
Sticker also states "Brushless", but aren't they all ? So not a criterion...
4) I am a bit worried about the orientation of two little, identical, 4 way connectors, on the edge of the digital board (CRT side). Picture below. I am worried because although I am 100% sure that I put them back in the same orientation they were when I took the scope apart (took plenty of pics at that stage, precisely to help me with re-assembly), I noticed that the Pin #1 on the cable, is NOT matching the Pin #1 labeled on the board, on the silk screen !
![Sad :(](https://www.eevblog.com/forum/Smileys/default/xsad.gif.pagespeed.ic.L3FGyzQrjB.png)
Looking at the board view in the service manual, these are connectors J2111 and J2112. Looks like they are directly related to some analog circuitry shaping the two channels before they are fed to the ceramic proprietary modules, one per channel. So, these connectors are bound to be important... so I would rather like to be 100% sure of their correct orientation...
Can anyone tell me how they are oriented on their scope, for those with a 2232 or similar ?
I mean, maybe it's "normal".. maybe it's a mistake from Tek, who got the Pin #1 marking wrong ? Happens even to the best I guess...
Things is, the scope has been opened before, by some previous owner, that's for sure as I found old flux on some reworked solder joints in the SMPS section of the main board. So maybe the guy who did that, put these two connectors the wrong way around, I can't know.
In the mean time, I will keep studying the service manual closely to try to figure it out...