Keyboard Shortcuts
Likes
- TekScopes
- Messages
Search
|
Re: 7854: Excessive stored trace brightness.
Rob
Thanks guys on the impromptu training on the 7854. I had thought to be
toggle quoted message
Show quoted text
helpful but I should have checked for similarities first before posting. At least it is good to hear that if/when I finally get one of those my experience in the other 7000's won't be a total waste. the readout is basically the same on all of the other scopes I have. Anyway, my hope is I did not confuse the original poster in my exuberance to finally have a chance of helping for a change *smile*. -----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of David Sent: Tuesday, July 10, 2012 10:14 AM To: TekScopes@... Subject: Re: [TekScopes] Re: 7854: Excessive stored trace brightness. The readout acquire uses the same ICs although it is encoded to binary and processed by the microprocessor before being displayed. I left out checking for the time slot pulse in my post. If it was missing, then there could be short/open or U2320 (155-0017-00) which is another custom Tektronix readout could be bad. On Tue, 10 Jul 2012 13:13:23 -0000, "Albert" <aodiversen@...> wrote: Sure, though readout acquire, as viewed from the plugins, is still the oldmethod. Missing units in readout could be caused by a fault during the corresponding time slot TS-9. I would first of all check for the presence of the -15V pulses at the main interface connectors, contacts B39. All 4 plugin positions have the B39 contacts in common so all should show the TS-9 pulse. Albert<david.partridge@...> wrote: logic boards. in a 7854. ------------------------------------ Yahoo! Groups Links |
|
Re: 7704A repair attempt, 155-0013-00 U2530
Rob
Are you double sure the connector between the bottom half and top half is
toggle quoted message
Show quoted text
plugged in tight, all associated connections/pins are tight, clean, etc.? All of my 7704A's had strange 'issues' at first. However after carefully cleaning this main card and card slot.--- (this was the biggest reason I had my series of questions on cleaning the card slot a while ago.... I am still not sure I have a good method...for the card yes...slot not so good...)---- In addition, check the associated cable plugs verifying all pins seated, etc.... Anyway, a lot of the strangeness went away and I was down to good old fashioned sensible troubleshooting after this step.. You will also want to double check all the ribbon cables plugging into the back side of the main board. They can get dirty and cause 'issues' as well. Anyway, if all that has been done I have to pass on the symptoms your describing. Haven't seen that yet. I will sit back and learn from the experts. As always I hope this helps. Rob -----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Fabio Eboli Sent: Tuesday, July 10, 2012 6:00 PM To: TekScopes@... Subject: [TekScopes] 7704A repair attempt, 155-0013-00 U2530 Hello, I bought a broken 7704A. The question: anybody knows the function of the 155-0013-00 IC ? Is possible to build an equivalent device, or to test one comparing it to another one? I have tree of them on the logic board and I'd like to know if one is faulty. I'm suspecting one of these 155-0013-00 in the logic board, but I'm not sure yet. The situation: The instrument shows a dot on the screen. No intensity regulation. The dot is strange, it's not a "good" dot. Once defocused it becomes an oblique and squared line, the astig. control isnt able to correct it. Focused it reduces to a diameter of about 2mm. The psu voltages are ok, only the ripple seem high, around 50mV on all the rails. The -2960V is high at about 3100V, once corrected the dot become very dim. I have these plugins, tested working: 7B92A 7A26 7A22 x2 I tried first with the 7A26 in the bays, vertical and horizontal position controls work on both Vertical bays and A Hor. bay. Hor. B slot isn't selected by the front selector. Once swapped the 155-0013-00 U2530 with U2535 the B hor. bay can be selected correctly. The timebase works correctly in vertical bays, triggers on line frequency in both Vertical bays, and shows a vertical line. In the orizontal bays the timebase doesnt work at all, the screen shows only a dot, the trigger doesnt light up also if I select line as trigger source. Any clue is welcome, as I have time I'll check the voltages and waveforms around. Fabio. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. ------------------------------------ Yahoo! Groups Links |
|
Re: Tek 465B Price
ken scharf
Currently I've seen reconditioned 465's in very clean condition selling for between $250-500 (really!) on ebay.
toggle quoted message
Show quoted text
On 07/10/2012 11:28 AM, Robert wrote:
Last fall I sold a good one in the SF bay area (Silicon Valley) for $130 |
|
Re: I have a type 585 oscope how much is it worth
I'd like to thank Casey for posting here; at least there's a fighting chance somebody with the proper inclination and skill will see it AND lives close enough to adopt it. Google says Scotts Mills is about an hour from the "mothership" (Beaverton), so I suppose there's hope.
toggle quoted message
Show quoted text
--- In TekScopes@..., "tubesnthings@..."<tubesnthings@...> wrote:
|
|
Re: Tek 468 problem
Ive added some photos of the scope displaying the fault. These are in my photo folder under bill.valvetechnology.
Ive checked the waveforms and ripple from both power supplies against the manual and both the analogue and digital power supplies look fine. Can anyone identify this fault? It has been suggested that it could be the clock signal being imposed on the waveform and the cursors in digital mode. Thanks Bill |
|
7704A repair attempt, 155-0013-00 U2530
Hello, I bought a broken 7704A.
The question: anybody knows the function of the 155-0013-00 IC ? Is possible to build an equivalent device, or to test one comparing it to another one? I have tree of them on the logic board and I'd like to know if one is faulty. I'm suspecting one of these 155-0013-00 in the logic board, but I'm not sure yet. The situation: The instrument shows a dot on the screen. No intensity regulation. The dot is strange, it's not a "good" dot. Once defocused it becomes an oblique and squared line, the astig. control isnt able to correct it. Focused it reduces to a diameter of about 2mm. The psu voltages are ok, only the ripple seem high, around 50mV on all the rails. The -2960V is high at about 3100V, once corrected the dot become very dim. I have these plugins, tested working: 7B92A 7A26 7A22 x2 I tried first with the 7A26 in the bays, vertical and horizontal position controls work on both Vertical bays and A Hor. bay. Hor. B slot isn't selected by the front selector. Once swapped the 155-0013-00 U2530 with U2535 the B hor. bay can be selected correctly. The timebase works correctly in vertical bays, triggers on line frequency in both Vertical bays, and shows a vertical line. In the orizontal bays the timebase doesnt work at all, the screen shows only a dot, the trigger doesnt light up also if I select line as trigger source. Any clue is welcome, as I have time I'll check the voltages and waveforms around. Fabio. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. |
|
Re: TDS 540 scope needs help
--- In TekScopes@..., "clboy168" <clboy168@...> wrote:
I find it most unlikely that both these chips have died. The outputs of these, as you marked, are 250 MHz ECL. The inputs (ACQCLK) are also as you marked but are 250 MHz on about +3VDC and not 1 GHz. These signals come from U1001 pins 20 and 21. U502 also have DLYCLK from the same source on pins 12 and 13. U1001 has its inputs (OSC500) on pins 40 and 41 which come from the VCO board (the small board monted vertically) on pins 2 and 3. This should be about 500 mVpp, 500 MHz on +3VDC. /H?kan |
|
Re: 7854 ROM Failure
¿ªÔÆÌåÓýGlad
it worked out.?
?
I lost
track of the thread but are the images archived somewhere?? If not, it
would be good to post them on several sites.? would be one I would think
of.
?
Thanks.
?
Joe
?
?
|
|
Re: I have a type 585 oscope how much is it worth
¿ªÔÆÌåÓýHi all,I am also in Germany, and have a 585 and a 585A (and some more....), and I will gladly drive some distance to give a good home to anoter of these very fine instruments. Of course, I also wouldn't decline a 547, 549, 555, (add some here!) I like to restore these great instruments, and the 585 (A) was the best you could buy for money at the time of its production. Think of it as a great car that is 50 years old: "Power nothing", an american used to describe these cars, but they are still loved oldtimers. I also think so about electronics. Regards, Jochen DH6FAZ Am 10.07.2012 21:33, schrieb
tubesnthings@...:
? |
|
2225 Scope PSU problem
EnBePe
I've just fixed a problem with the PSU in one of my 2225 scopes. It turns out that three capacitors had gone s/c; C986/988/990, all 1000uF/16V electrolytics on the three LV lines +/-8.6V and +5.2V.
They were Rubycon types which I'd always thought were supposed to be OK; was there a batch problem in production or a poorly specified part being used here? Just wondering whether I'll get a repeat problem later. The voltage rating seems well in tolerance but of course these are getting hit with 20KHz ripple and that's a different story. The scope seems as bright as a button now. |
|
Re: Help with R7903 needed, some success...
It ends up that my paper 7904 manual is incomplete and missing
schematic 11 so I have nothing to scan. Some of the earlier schematic pages were inserted backwards so maybe it was disassembled at some point. On Tue, 10 Jul 2012 12:38:31 -0500, David <davidwhess@...> wrote: I was afraid of that. I will make a good scan of the 7904 schematic |
|
Re: I have a type 585 oscope how much is it worth
No argument; epic but nearly useless because of only 4 cm vertical deflection. I am preserving two 585As with all five plug-ins ever made for it, including the cal unit and both versions of the 81 adapter. The seller made me buy them to get my hands on some 547s I wanted. Guess he was expecting to get stuck with them and having to live with his only other option¡ Gladly took them and will pick up all in driving range - but I'll probably never use any of them (contrary to other models; 547, 556, 561, 565, 503¡). FYI am in Northern California and will travel to rescue all I can. Bernd Schroder Sent from my Verizon Wireless Phone -----Original message-----
|
|
Re: 7854: Excessive stored trace brightness.
Albert
Hi David,
toggle quoted message
Show quoted text
When readout intensity is ok then there is not much room left for faults in stored mode waveform intensity. The path for the "intensity setting current" starts at the intensity pot A5R65, signal WFMINT, diagram <11>. Then WFMINT is used in A21 <13> (for other purposes) and also passed to A29 <34>, A29Q1830, a CA3046 transistor array. The output ROZAXIS is common for readout intensity and stored waveform intensity. Switching between these is done by ~CHRZON and ~WFMZON. The simplest fault would be that the ground terminal of R65 is disconnected internally. Then you still have smooth operation but you can't reduce intensity far enough. Try to measure resistance from slider to ground, perhaps via A29R1832|R1831 (that would need removal of board A29?) if you can't reach the pot. I'm afraid the board locations are such that you need extender boards for measurements on the working 'scope. Q1830 and Q1930 are of the same type but swapping these 5-fold arrays might produce other problems. Albert --- In TekScopes@..., David Holland <david.w.holland@...> wrote:
|
|
Re: I have a type 585 oscope how much is it worth
That ist right.
toggle quoted message
Show quoted text
585, 581 are a epic technologiy. high bandwith, distributed deflection and tunneldiode -base triggering (only with A-version) [url][/url] Picture of T581 CRT, ³Ò°ù¨¹²õ²õ Matt --- In TekScopes@..., jerry massengale <j_massengale@...> wrote:
|
|
Re: 7854 ROM Failure
Hi All
toggle quoted message
Show quoted text
Good news, my 7854 is up and running again! I got the replacement ROM,s from buyicnow.com as suggested, they were able to program them as well. Delivery was super fast! Thanks to you all for your help!!! Cheers Adrian --- In TekScopes@..., "J. L. Trantham" <jltran@...> wrote:
|
|
Re: Help with R7903 needed, some success...
keithostertag
Photos of TP1801, TP1805, TP1827:
After I made these I realized that I hadn't paid any attention to the exact setting of the Intensity control... I don't see (on the schematic) how to set the Intensity to correspond to the waveforms shown on the schematic. Can you say? Should it be set to maximum? The above traces are with the Intensity set about midway, same setting through all three TP's. Ground ref is center line of grid. I'm not sure, but don't the waveforms on the schematic show a negative bias to these? Am I coupling wrong? I've already posted waveforms for TP1801 and TP 1805 on DC coupling. Thanks, Keith Ostertag |
|
Re: I have a type 585 oscope how much is it worth
Hi,,
toggle quoted message
Show quoted text
Destroying a 585 for it's tubes is like Tearing down The Statue of Liberty to build a parking lot. Jerry Massengale
-----Original Message----- From: d.seiter To: TekScopes Sent: Mon, Jul 9, 2012 11:38 pm Subject: Re: [TekScopes] Re: I have a type 585 oscope how much is it worth
?
I overheard a guy at the DeAnza flea market a few years ago tell about how he would wipe the markings off tubes and remark with a marker so the hard core tube vultures wouldn't want the scopes/tubes he was selling, but the people who would actually use the scopes wouldn't care.
Seemed kind of extreme...
-Dave
From: "mattko87" <matt8@...> To: TekScopes@... Sent: Monday, July 9, 2012 9:20:32 PM Subject: [TekScopes] Re: I have a type 585 oscope how much is it worth ? --- In TekScopes@..., "casey" wrote: > > Hello this is Casey Berg from Scotts Mills. > > I recently obtained a type 585 oscope. It works but I think it needs some calibration. are there any interested buyers. > > It also comes with a cart. > > Please add me to skype my user id is caseyberg88 > Hi Don?t sell him over eBay and other plattform, because audio people will killing them for 6DJ8. In Germany are selling many 585 to this idiots. You can pull out 6Dj8, put russia 6922 into 585. You will seeing, interested buyer will be reduced, because some are a tube vulture ;-) Regards matt |
|
Re: 224 Battery Pack
Thanks to those who supplied links, I'll try the Cyclon from Mouser or gotbatteries.com.
toggle quoted message
Show quoted text
Larry --- In TekScopes@..., "Scott O'Connell" <scotto@...> wrote:
|
zenith5106
David Hess