Someone really did a number on that scope a shame, best bet is buy another for donor unit as parts can add up quickly especially considering knobs is broken and etc and missing components likely as you stated to be sold and they go for about $55 bucks. Good step forward at least.
Not a bad idea! The total for cost is already starting to add up for this one - NOS attenuators, hardcopy of service manual (I cannot read the damn waveforms clearly on any of the PDF versions I've found online) and I bought a set of ROM chips just in case the digital fault is due to those being faulty. This likely will not be an ecomonically beneficial repair, but I did not buy it necessarily for that reason. I could have likely bought a working one of these scopes for ~$100. I bought moreso because I thought it would make for an interesting repair project! Was not expecting someone to have had attempted repair already like this though!
Hello Frankie! Something I forgot to tell you abpit thst broken knob off Ch-2! Hop you havn’t chucked it out yet! You can glue it back together. I think those knobs are made from ABS, (Acrylonitrile-Butsdiene-Styrine co-polymer)…here in Oz, PSTN telephones were made of this stuff…and it is damn tough and can take a lot of physical abuse. It dissolves in chlorinated solvents, particularly di-chloro-methane, (CH2Cl2) or chloroform, (CHCl3). In your case you only need the TINIEST ammount of such a solvent to use as s glue…I would glue the knob in place on the shaft…(It won’t be glued TO the shaft and you should be able to pull it off complete after the solvent evaporates). just put the broken collar back onto the switch shaft, then fet a hypodermic needle and dip it int a bottle cap with a few mililiteres of choroform in it. Capillary action will draw some chloroform up inside the hollow space inside the needle, (you might need to file or dremel the sharp tip off the needle), then just touch the tip of the needle full of solvent to the rough borken end of the knob collar…quickely, before it evaporates, slide the rest of the knob down the shaft, make sure the phase angle between the two pieces is 0 and push them together firmly…the shaft of the swotch will keep them aligned and stop the ABS “gooping” into the shaft hole st the join. Give it about two hours if you use dichloromethane and four hours if you use chloroform. You can make chloroform fron acetone and sodium hypochlorite but you will need a reflux setup you can then reconfigure to simple distillation. Outher you tubers have done it, so just go and watch them to get all the intricate details, but a 50ml bottle of chloroform on the electronics bench is always useful. I took a look at the inpu amps on this CRO, I see that a CMOS op-amp, (TLC271, Texas Linesr Cmos) does the low frequency buffering snd the usial j-FET does the high frequency buffering st the input…clever design, I must say! I also see that the signal will reach the input from the BNCs (with the two PI attenuators missing) if yiu set it to leat attenuation…so you can get a signal into it and go along the signsl path with the 54600 whilst you wait for the attenuators to come. The fact you got the cal signal right through to the deflection plates on Ch-1 is GREAT. Try to put a sine ir triangle wave through it, this will show you if any stages are clipping or saturating. Love to see you try Ch-2 and see if U80 is OK! Just a little history of CRO’s. The very first CRO’s had no Y-Amps, the test signals were simply applied directly to the deflection plates of the tube! This is why all REAL analog CRO’s use an electrostatic tube because its response time is really FAST! So, basically a broadbabd amplifier…”from DC to daylight” grts the signal to the plstes and the tube does the rest. Much later, when FAST ADC’s or samplers were developed, these could replace the tube as the recipients of the broadband signal..digitize it, store it and then read it out slow to be displayed on a SLOW as a wet week electromagnetic tube, sometimes as a TV raster…this is what your 54600 Does. To me, an electromagnetic deflection tube displaying an oscilloscope trace as a raster just dies not have the “charm and mistique” of a FAST, real-time high quality electrostatic tube! did you know that RAELLY old TV’s use electrostatic tubes? You will warm to the charm of the electrostatic tube. I have a HP 54600, but I arely ever use it, simply because I much prefer one of my many lovely electrostatoc tube CRO’s! But, as they say, “you need a CRO to fix a CRO”…and I agree, life would be a lot, lot harder without thet 54600 at your disposal. Oh, can you do a short follow-up closure/debrief video on the HP power supply. Love to see it all cleaned up ind fully functioning as part of your bench gear!
Thank you Globe Collector (if you'd like me to call you Andrew instead I can, I just think Globe Collector is a badass nickname!) as always for your detailed input and feedback! So my main job is working as an in-house engineer for a biotech company (I use to work as a chemist actually). We don't keep solvents like that, but I can order some. I kept the parts of the channel 2 knob. It broke very clean so I was thinking of gluing it back together, just wasn't sure what adhesive to use. As you know, those knobs take a pretty good deal of tangential force to turn them. I didn't think the knob would hold up well, but I would be willing to give your method a try! Thanks for the suggestion about setting Volts/div to lowest setting to get the signal to pass thru the vertical preamps/amplifiers! I ordered the attenuators - they should be here before the new year! I was aware of the extensive use of CRTs before the advent of LCDs. I've worked with them before in other test equipment I own. Just never owned a nice analog scope like this before. Really hoping to get it back up and running. I can do a follow-up on the HP supply! In fact, the GPIB controller that I ordered came in. So now I can do the calibration procedure. I just need to install the software on my PC. Thanks again for your input!!!
That’s what your name is for! It is the only thing the belongs to you…but everybody else uses it but you! I am also called, “sparky”, “perky” and “boof-head”….don’t come to Australia if you don’t like nicknames, brcause everybod gets one…or two, or three here! Scuse the typos, using a i-pad on-screen keyboard is very difficult. I am called “Globe-Collector” because I collect light globes, (light-bulbs in the language you use over there), it is that simple! I am fixing and videoing Tektronix 7L5 spectrum analyser at present. It is about as bad as your 2230 there, bits missing, it has been dropped…so broken and missing knobs, bent pot and switch shafts, cracked die cast front sub pannel. I had two tants short out and go up in smoke at first power up…so I changed the lot. It dtill has issues in the two phase locked loops that set the frequency of the first local oscillator. There sre two phase comparators based around very high impedance integrating sample snd hold circuits, where a voltage is stored in a very high quality capacitor…like the ones in your B-Tine base there…this voltage is buffered with a very swanky Analog Devices op-amp and the capacitor has to hold 98% of it voltage gor st least 100 seconds…that’s FENTO amos of leakage! Cap scharged (or discharged) via two diodes, (both on the same TO-72 can) thst posess less than 1pA leakage…the best modern SMD diodes are three orders of magnitude worse at 1nA! So I have “my fun” cut out gor me for the rest of the summer. Wishing you and your partner a happy, calm and stressless Christmas from “downunder”!
That's awesome! I look forward to seeing your video of this repair if you plan to post it on here! Merry Christmas to you and your wife as well! @@thanhhuynh272
Nice steps forwards, as you say somebody did a real number on this scope. Great work.....cheers.
Thanks as always for watching!
Good job!
Someone really did a number on that scope a shame, best bet is buy another for donor unit as parts can add up quickly especially considering knobs is broken and etc and missing components likely as you stated to be sold and they go for about $55 bucks.
Good step forward at least.
Not a bad idea! The total for cost is already starting to add up for this one - NOS attenuators, hardcopy of service manual (I cannot read the damn waveforms clearly on any of the PDF versions I've found online) and I bought a set of ROM chips just in case the digital fault is due to those being faulty. This likely will not be an ecomonically beneficial repair, but I did not buy it necessarily for that reason. I could have likely bought a working one of these scopes for ~$100. I bought moreso because I thought it would make for an interesting repair project! Was not expecting someone to have had attempted repair already like this though!
Hello Frankie! Something I forgot to tell you abpit thst broken knob off Ch-2! Hop you havn’t chucked it out yet! You can glue it back together. I think those knobs are made from ABS, (Acrylonitrile-Butsdiene-Styrine co-polymer)…here in Oz, PSTN telephones were made of this stuff…and it is damn tough and can take a lot of physical abuse. It dissolves in chlorinated solvents, particularly di-chloro-methane, (CH2Cl2) or chloroform, (CHCl3). In your case you only need the TINIEST ammount of such a solvent to use as s glue…I would glue the knob in place on the shaft…(It won’t be glued TO the shaft and you should be able to pull it off complete after the solvent evaporates). just put the broken collar back onto the switch shaft, then fet a hypodermic needle and dip it int a bottle cap with a few mililiteres of choroform in it. Capillary action will draw some chloroform up inside the hollow space inside the needle, (you might need to file or dremel the sharp tip off the needle), then just touch the tip of the needle full of solvent to the rough borken end of the knob collar…quickely, before it evaporates, slide the rest of the knob down the shaft, make sure the phase angle between the two pieces is 0 and push them together firmly…the shaft of the swotch will keep them aligned and stop the ABS “gooping” into the shaft hole st the join. Give it about two hours if you use dichloromethane and four hours if you use chloroform. You can make chloroform fron acetone and sodium hypochlorite but you will need a reflux setup you can then reconfigure to simple distillation. Outher you tubers have done it, so just go and watch them to get all the intricate details, but a 50ml bottle of chloroform on the electronics bench is always useful.
I took a look at the inpu amps on this CRO, I see that a CMOS op-amp, (TLC271, Texas Linesr Cmos) does the low frequency buffering snd the usial j-FET does the high frequency buffering st the input…clever design, I must say! I also see that the signal will reach the input from the BNCs (with the two PI attenuators missing) if yiu set it to leat attenuation…so you can get a signal into it and go along the signsl path with the 54600 whilst you wait for the attenuators to come. The fact you got the cal signal right through to the deflection plates on Ch-1 is GREAT. Try to put a sine ir triangle wave through it, this will show you if any stages are clipping or saturating. Love to see you try Ch-2 and see if U80 is OK!
Just a little history of CRO’s. The very first CRO’s had no Y-Amps, the test signals were simply applied directly to the deflection plates of the tube! This is why all REAL analog CRO’s use an electrostatic tube because its response time is really FAST! So, basically a broadbabd amplifier…”from DC to daylight” grts the signal to the plstes and the tube does the rest. Much later, when FAST ADC’s or samplers were developed, these could replace the tube as the recipients of the broadband signal..digitize it, store it and then read it out slow to be displayed on a SLOW as a wet week electromagnetic tube, sometimes as a TV raster…this is what your 54600 Does. To me, an electromagnetic deflection tube displaying an oscilloscope trace as a raster just dies not have the “charm and mistique” of a FAST, real-time high quality electrostatic tube! did you know that RAELLY old TV’s use electrostatic tubes? You will warm to the charm of the electrostatic tube. I have a HP 54600, but I arely ever use it, simply because I much prefer one of my many lovely electrostatoc tube CRO’s! But, as they say, “you need a CRO to fix a CRO”…and I agree, life would be a lot, lot harder without thet 54600 at your disposal.
Oh, can you do a short follow-up closure/debrief video on the HP power supply. Love to see it all cleaned up ind fully functioning as part of your bench gear!
Thank you Globe Collector (if you'd like me to call you Andrew instead I can, I just think Globe Collector is a badass nickname!) as always for your detailed input and feedback! So my main job is working as an in-house engineer for a biotech company (I use to work as a chemist actually). We don't keep solvents like that, but I can order some. I kept the parts of the channel 2 knob. It broke very clean so I was thinking of gluing it back together, just wasn't sure what adhesive to use. As you know, those knobs take a pretty good deal of tangential force to turn them. I didn't think the knob would hold up well, but I would be willing to give your method a try!
Thanks for the suggestion about setting Volts/div to lowest setting to get the signal to pass thru the vertical preamps/amplifiers! I ordered the attenuators - they should be here before the new year!
I was aware of the extensive use of CRTs before the advent of LCDs. I've worked with them before in other test equipment I own. Just never owned a nice analog scope like this before. Really hoping to get it back up and running.
I can do a follow-up on the HP supply! In fact, the GPIB controller that I ordered came in. So now I can do the calibration procedure. I just need to install the software on my PC.
Thanks again for your input!!!
That’s what your name is for! It is the only thing the belongs to you…but everybody else uses it but you! I am also called, “sparky”, “perky” and “boof-head”….don’t come to Australia if you don’t like nicknames, brcause everybod gets one…or two, or three here!
Scuse the typos, using a i-pad on-screen keyboard is very difficult.
I am called “Globe-Collector” because I collect light globes, (light-bulbs in the language you use over there), it is that simple!
I am fixing and videoing Tektronix 7L5 spectrum analyser at present. It is about as bad as your 2230 there, bits missing, it has been dropped…so broken and missing knobs, bent pot and switch shafts, cracked die cast front sub pannel. I had two tants short out and go up in smoke at first power up…so I changed the lot. It dtill has issues in the two phase locked loops that set the frequency of the first local oscillator. There sre two phase comparators based around very high impedance integrating sample snd hold circuits, where a voltage is stored in a very high quality capacitor…like the ones in your B-Tine base there…this voltage is buffered with a very swanky Analog Devices op-amp and the capacitor has to hold 98% of it voltage gor st least 100 seconds…that’s FENTO amos of leakage! Cap scharged (or discharged) via two diodes, (both on the same TO-72 can) thst posess less than 1pA leakage…the best modern SMD diodes are three orders of magnitude worse at 1nA! So I have “my fun” cut out gor me for the rest of the summer.
Wishing you and your partner a happy, calm and stressless Christmas from “downunder”!
That's awesome! I look forward to seeing your video of this repair if you plan to post it on here! Merry Christmas to you and your wife as well! @@thanhhuynh272