You know how sometimes the Universe just sends you signals, perhaps to remind you that you are on the right path?
Well, this morning I received a phone call from the man who often supplies test equipment. He has a friend who buys up the assets of failed companies and when test stuff appears, I generally get a call. They just want rid of it and often pretty much give it away. I've bought too much to remember, however two items which spring to mind are spectrum analyzers, a HP 8569B for (the equivalent in Brazil) less than 20 Dollars and a Tek 492 for 35 Dollars. Both with failed PSU's and both fully functional following simple repairs. Insane! Although I mustn't forget the 'dead' (yet calibrated) Fluke 289 for 40 Dollars which only had a bad battery connection and is now my most accurate DMM.
Anyways, I digress... This morning, he rings me up to offer me two scopes for 50 Dollars. Would you believe it that one was a 2430A!?!? Lol
The other was/is a TAS 465 which he said was missing a board, but looking at the manual and a teardown, it appears to be complete. The problem being that it only displays a stationary 'dot' in the middle of the display.
So, opening up the new 2430A, revealed that on the top board, two tantalums had totally burned up, ironically including the 2.7?F one mentioned earlier in this thread..
Seemed reasonable to just switch the board from my blurry 2430A and sure enough the 'new' scope came to life, displaying the diagnostic menu et al.
Unsurprisingly it has various 'FAILS' however, it now gives the opportunity to switch boards and Hybrids in order to hone in on any problems.
The TAS 465 shall have to wait.
Addendum... The TAS 465 (which had been left plugged in but off) just went pffffftah! and dumped out a whole load of smoke. Guess I now know where to start.. :)
James
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Re: Tek 2236 Control Button Error
Check harmonica connectors from panel to other boards possible to reseat.
Jon
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Tek 2236 Control Button Error
Recently my Tek 2236 began giving a "Control Button Error" message, occasionally at first and now more regularly. Exercising the buttons does not seem to clear this. I ran the CTM diagnostic and everything passes except reading the 1X/10X CH1 sense ring, always indicating "P0" even when the ring is grounded (I don't know if it ever did sense correctly, as I generally used non-encoding probes anyway). In the diagnostic, it reliably reads the positions of all other switches, in particular indicating the push button positions solidly, no glitches seen in the 1/0 transitions in the diagnostic display.
Sometimes with no input I get the "OUCH" message on CH1 volts (even with the input set to ground). Otherwise, all of the CRT display functions appear unaffected.
When the CTM is working, everything works in the alphanumeric display, when not, I get the scrolling "Control Button Error" message, nothing works in any button configuration.
Anyone have any thoughts on this?
I have several Tek scopes, analog, full digital, storage (for a 5L4N) and a 4 channel. However the 2236 is my favorite for general bench work. I miss the built-in frequency counter...
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Hello, The truth is that I took a while to post because I didn’t have the money to buy the spare parts. I had to work extra hours for two months to afford them. I'm sorry.
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In fact Mark, I actually have here a HV board with a blown transformer so I can grab the resistors from that . If for nothing else other than to see what happens?
Thanks again
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Thank you Mark.
I'll look into that and let you know how it goes..
James
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Tektronix 2712 Amplitude Normalization Fail
Hello I have a 2712 that i picked up “parts only” on eBay. I replaced the two button cells and it works well aside from failing two Amplitude Normalizations.
BW Filter Ampltd (Lin) FAIL
Preamp & Det Gain FAIL
Wondering if anyone can point me in the right direction so I can fix it.
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James,
Likely the resistors to the C and B of Q145, Q152 and Q269 collector only are bad. The originals are stressed. Use 1W types. These are the same problem in the 24x5/7 series. Even if they test alright, they could be bad in operation. Get resistors physically larger to take the higher voltage drop. Ones about 10mm long work fine. Mouser has a wait of 12 weeks for 442,000 ohm resistors. A pair of 1/2W 221,000 ohm resistors in series will work.
Mark
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But this scope has a display (now).
Just ridiculously blurry
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Re: [HP-Agilent-Keysight-equipment] I need a new/used lab computer
Looks like he needs a PCI slot for gpib card. Would have to go to USB to GPIB if he went w a laptop.
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On Mar 6, 2025, at 15:27, Harke Smits via groups.io <yrrah@...> wrote:
?Jim,
Do you have anyone in your environment with a not too old laptop? Get it for a box of cigars, install an SSD and Linux Mint. You're back in business!
Best 73 de Harke
On 6-3-2025 21:24, Jim Ford via groups.io wrote:
My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
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Re: I need a new/used lab computer
Well, I was hoping to get something quickly to do some experiments with the PS5004 power supply plug-ins I just bought recently. Rather painful to adjust a 20 V supply in 500 uV increments! But you are more than welcome to stop by my house. I will be on vacation from Th 3/13/25 to F 3/21/25, but a visit after that would be great. I’m right off the 5 San Diego freeway.
Thanks!
Jim
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On Mar 6, 2025, at 12:59?PM, Tom Lee via groups.io <tomlee@...> wrote:
?If you can wait a month or so, I may be able to hand-deliver it to you on my way to visit family in San Diego.
Tom
Sent from an iThing; please forgive the typos and brevity
On Mar 6, 2025, at 12:44, Jim Ford via groups.io <james.ford@...> wrote:
?Thanks, Renee. LMK. Shipping should be reasonable down here to So Cal. Jim
On Mar 6, 2025, at 12:43?PM, JAMES FORD <james.ford@...> wrote: ?Maybe. I don’t find any PCs in ewaste at work, probably because of proprietary information on the hdds. I will ask around. Thanks. Jim
Sent from my iPhone
On Mar 6, 2025, at 12:24?PM, Jim Ford via groups.io <james.ford@...> wrote: ?My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
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Re: 2465A start-up problem
George,
Where is it on the spec sheet that is says 350 V NOT 500V? ,
Mark
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Re: I need a new/used lab computer
If you can wait a month or so, I may be able to hand-deliver it to you on my way to visit family in San Diego.
Tom
Sent from an iThing; please forgive the typos and brevity
toggle quoted message
Show quoted text
On Mar 6, 2025, at 12:44, Jim Ford via groups.io <james.ford@...> wrote:
?Thanks, Renee. LMK. Shipping should be reasonable down here to So Cal. Jim
On Mar 6, 2025, at 12:43?PM, JAMES FORD <james.ford@...> wrote:
?Maybe. I don’t find any PCs in ewaste at work, probably because of proprietary information on the hdds. I will ask around. Thanks. Jim
Sent from my iPhone
On Mar 6, 2025, at 12:24?PM, Jim Ford via groups.io <james.ford@...> wrote: ?My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
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Re: I need a new/used lab computer
Thanks, Renee. LMK. Shipping should be reasonable down here to So Cal. Jim
toggle quoted message
Show quoted text
On Mar 6, 2025, at 12:43?PM, JAMES FORD <james.ford@...> wrote:
?Maybe. I don’t find any PCs in ewaste at work, probably because of proprietary information on the hdds. I will ask around. Thanks. Jim
Sent from my iPhone
On Mar 6, 2025, at 12:24?PM, Jim Ford via groups.io <james.ford@...> wrote:
?My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
|
Re: I need a new/used lab computer
Maybe. I don’t find any PCs in ewaste at work, probably because of proprietary information on the hdds. I will ask around. Thanks. Jim
toggle quoted message
Show quoted text
On Mar 6, 2025, at 12:24?PM, Jim Ford via groups.io <james.ford@...> wrote:
?My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
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Re: [HP-Agilent-Keysight-equipment] I need a new/used lab computer
Jim-
let me check as I have a tower doing nothing...hss not been used for long time, will know when I get to the shop over the weekend.
shop is? in no. SF bay area
搁别苍é别
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On 3/6/25 12:24 PM, Jim Ford via groups.io wrote: My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
.
|
Re: [HP-Agilent-Keysight-equipment] I need a new/used lab computer
Jim,
Do you have anyone in your environment with a not too old laptop? Get it for a box of cigars, install an SSD and Linux Mint. You're back in business!
Best 73 de Harke
toggle quoted message
Show quoted text
On 6-3-2025 21:24, Jim Ford via groups.io wrote: My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
|
I need a new/used lab computer
My garage lab computer went kaput recently, and I need to get another one to control my instruments via GPIB and USB. I had a tower running Windows 7, although it was originally my wife’s computer running (ick!) Windows Vista. Sooooo slow! Anyway, I don’t need anything fancy, just a PCI slot for the GPIB card, Ethernet jack for Internet connection, and at least 4 USB jacks (kbd, mouse, USB microscope, GPSDO). Mini tower or thin client would be great. Anybody have a PC they don’t need? Thanks in advance.
Jim Ford
Laguna Hills, California, USA
|
Re: 2465A start-up problem
Hi
NO NO NO Standard 1W resistors only have a working voltage of 350V and some of rare ones of 500V, use resistors from the Vishay VR range or equivalent. R4434 must be suspected.
G Edmonds On Thursday 6 March 2025 at 16:34:03 GMT, Mark Vincent via groups.io <orangeglowaudio@...> wrote:
James,
The focus problem may be due to resistors in and around the focus circuit. They should be raised to 1W types due to the voltage drop across them. These resistors are from B+ to the collectors and from C to B of a few transistors on the h-v board. The part numbers are from Mouser. The 150,000 ohm: 71-CCF60-150K-E3, 180,000 ohm: 279-H4P180KFDA, 332,000 ohm: 71-CCF60-332K-E3, 442,000 ohm: 71-CMF60442K00FEWF (12 week delay) or (2) 660-MF1/2CC2213F (in series), 430,000 ohm: 279-H4P430KFZA, 100meg: 708-HVA12FA100M or (measure in mm the hole spacing of the original carbon then select the on that will drop in which will be larger in wattage than original). If yours has the two 39meg 1/4w carbons on the bottom board, use two 594-MBE04140C2005FC1 in series. These will be R710 and R910.
When you finish recapping the unit, use high temp, low ESR and long life types. Make sure to get the polarity and look to see if yours has the incorrect voltage and values of two condensers in the supply. Replace them as you find them. There are resistors in the supply that should be increased in wattage. The two 4,7mfd tantalums likely will test bad. I used 50V film types to replace them. M. Yachad has a kit for these to recap and some resistors that should be replaced.
Mark
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Re: 2465A start-up problem
James,
The focus problem may be due to resistors in and around the focus circuit. They should be raised to 1W types due to the voltage drop across them. These resistors are from B+ to the collectors and from C to B of a few transistors on the h-v board. The part numbers are from Mouser. The 150,000 ohm: 71-CCF60-150K-E3, 180,000 ohm: 279-H4P180KFDA, 332,000 ohm: 71-CCF60-332K-E3, 442,000 ohm: 71-CMF60442K00FEWF (12 week delay) or (2) 660-MF1/2CC2213F (in series), 430,000 ohm: 279-H4P430KFZA, 100meg: 708-HVA12FA100M or (measure in mm the hole spacing of the original carbon then select the on that will drop in which will be larger in wattage than original). If yours has the two 39meg 1/4w carbons on the bottom board, use two 594-MBE04140C2005FC1 in series. These will be R710 and R910.
When you finish recapping the unit, use high temp, low ESR and long life types. Make sure to get the polarity and look to see if yours has the incorrect voltage and values of two condensers in the supply. Replace them as you find them. There are resistors in the supply that should be increased in wattage. The two 4,7mfd tantalums likely will test bad. I used 50V film types to replace them. M. Yachad has a kit for these to recap and some resistors that should be replaced.
Mark
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James55
Jean-Paul
bownes