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Re: [TekScopes2] Re:Replacing caps
davec
If I have a whole bunch to replace, I use solder paste, hot air, and a-=-=-=- No hot air SMT apparatus or oven. Will be using fine tip iron. Can you actually touch the tip to the caps' leads while the cap is resting in place? Or do you heat the pad while pressing down on the cap? (Flux paste is probably a good idea, too, I'd think...) Thanks, Dave |
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Re: Replacing caps (was: Help with Tek 2445)
davec
Chuck,
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What about the small SM electro caps? Seems to me that these might be difficult to solder (being originally wave soldered) -- getting an iron in there might be difficult. I read that some folks use radial caps with very short, bent leads soldered to the pads. Your experience? Thanks, Dave -=-=-=- Hi Dave, |
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Re: Type 111 Pretrigger Pulse Generator not up to speed
--- In TekScopes@..., "Craig Sawyers" <c.sawyers@...> wrote:
I've got a chicken-and-egg problem here. I have a pile of 560-type sampling plugins thatSubject: [TekScopes] Type 111 Pretrigger Pulse Generator notTrying to deconvolve a fast rise time from a longer one is fraught with I want to fix up, and need to get the 111 going to help do that :) Right now I'm borrowing time on a modern Tek TDS4000 series. 350MHz digital phosphor unit. I have heard that the frequency response of the recent digital scopes is not guassian - that the rise time is somewhat faster than bandwidth alone would indicate. That makes me think that my estimate of 111 risetime is actually erring on the high side. Mostly I'm just glad it works at all, actually, I shouldn't complain too hard. I suppose the 3S gear and the 111 can bootstrap themselves up to speed, one step at a time. |
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Re: Tek 315D Oscilloscope Instruction Manual
--- On Fri, 9/19/08, Pierre F1BLF <pierrot8254@...> wrote:
From: Pierre F1BLF <pierrot8254@...> Subject: [TekScopes] Tek 315D Oscilloscope Instruction Manual To: TekScopes@... Date: Friday, September 19, 2008, 9:29 PM Hi Tekscopers, I'm looking for a Tek 315D Instruction Manual, preferably in a scanned form of PDF. Many thanks in advance. Pierre F1BLF I could use one of those manuals too as I have one of those fine old relics in my collection. It is the only scope I have that I seriously thought of washing as it's the filthiest. Has broken fan mounts thanks to UPS but otherwise it is in very good physical condition. Complete with stacks of selenium rectifiers with a sticker that fell off stating that those had been replaced ages ago. Also contains plenty of "bumblebee" caps. Think I might be missing a cover plate over the HV section though. Occasionally I'll look at the scope but not planning on restoration any time soon, mainly due to the washing issue keeping me from even getting started. I?have?the scoped?wrapped in plastic so it doesn't get any dirtier! ? ? Sorry to hijack the message. A few good pics in?there of the little beast if you care to look. ? ? Dave |
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Somewhat OT: HP 8553B/8443A system needs new home (Los Angeles area)
All,
I posted this on the HP/Agilent group and haven't had anyone jump at the chance to pick this stuff up: I have upgraded my spectrum analyzers and I no longer have room for the old units. The following items are available free to anyone who can use them and is willing pick them up. (I live in Venice, California.) 140T/8552B/8553B system with a 8443A (late model, LED) tracking generator. 2 each 8556A 8250A storage normalizer Tek 604 monitor (use with 8250A) HP 1331A variable persistence display Let me know if you are interested. -- John Gord ( johngord(at)verizon.net ) |
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Re: Type 111 Pretrigger Pulse Generator not up to speed
Craig Sawyers
Subject: [TekScopes] Type 111 Pretrigger Pulse Generator notTrying to deconvolve a fast rise time from a longer one is fraught with problems. 500ps on a 1ns instrument response is a nominal 1.12ns - which is only 14% different from your measured 1.275ns. Are you sure your timebase is that accurate on the fastest sweep ranges (they often aren't). The only sure way to measure it more accurately is to use something with a response much faster than what you are trying to measure - ie a sampling set up (which is precisely what the pretrigger of the 111 is for - getting the sampling timebase up and running before the measurement event). To get a good grip on the rise time and potential aberrations, you need a rise time at least three times faster than what you are trying to measure (for a 10% error). So at most at 170ps rise time. An S2, S4 or S6 sampling head will do this, or a 1S2 from the earlier generation. My main scope is set up with a spectrum analyser at the moment, or I would get sampling up and running and measure my own type 111. It would just be confirmation though - I've measured it before, and know for certain that it gives less than 500ps rise. Craig |
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Option 13 in an R7912?
Jose V. Gavila
Hello!
Today I have received my last Tek toy, an R7912 mainframe :-). It has a label in the plug-in compartment base which says 'Option 13'. I wonder if someone know what does it mean. Thanks! JOSE ------------------------------------------------- 73 EB5AGV - JOSE V. GAVILA IM99sm La Canyada - Valencia (SPAIN) Vintage Radio and Test Equipment European Boatanchors List Amateur Repairs List |
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Need 475 scope
Dave_s
Hi folks,
The repair of my sick 475 scope is not occurring EASILY despite SO AMNY HELPFUL suggestions from members of this group. It is possible that the repair may occur. Just in case, I am now searching for a replacement usable 475, 475A, or 485 in good working condition. What is available? Never having used EBAY, I am also interested in other sources that refurbish, calibrate, offer good used scopes, etc. Still optimistic that I will find the fault parts. Thank you, 73, W6MIK, Dave |
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Re: 2215 Problem
tom jobe
Hello Gary,
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For what it's worth... That same capacitor, 285-1222-00, was also used in the military version of the 2235, It was used directly across the incoming AC lines just before the full wave bridge rectifier as part number C904, and it did not have a resistor in series with it.. I have a few partially stripped military 2235 mainboards, and they are all missing C904, so I would guess that it must have been a component that had problems. Other 22XX scopes I looked at use a .0022 uF (2200 pF) 250 V capacitor for C904. tom jobe... ----- Original Message -----
From: "Garey Barrell" <k4oah@...> To: "Tekscopes" <TekScopes@...> Sent: Thursday, September 18, 2008 7:55 PM Subject: Re: [TekScopes] 2215 Problem Stefan -come fingersfrom singapure, and worked just fine for a few hours beforehand. module.for days. The cap was actually inside a Schaffner brand mains filter <k4oah@...>wrote: toI was using my 2215 for an hour or so the other night, and moved over likethe desk to look at something else. About 30 minutes later I heard a thea Rolodex. P/N 285-1222-00, 0.068 uF @ 250 VDC, 20%. This is a tiny one.million and a half capacitors that I have will even come close to ------------------------------------ |
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Re: 2445 vs 2465 scopes
The first problem I had with my 2445 was a PSU problem. I had
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massive noise on the -15v unreg line, causing severe jitter on the display. Turned out to be a leaky C1113 on the inverter board (A3). I know what you mean about accessing the PSU boards. Some parts of the removal procedure didn't seem to make any sense in the 2445 manual (especially the bit about removing the fan blade???). The procedure in the 2465 manual was clearer. My main concern was replacing all the multiway connectors once the boards were refitted to the chassis. It's easy pulling them off, but reconnecting them! Luckily my young nephew was on hand (with smaller, more nimble fingers, and better eyesight than mine) to reconnect them for me. :) --- On Thu, 18/9/08, Philip Parsons wrote:
Date: Thursday, 18 September, 2008, 4:03 PM Hi, The 10V supply is actually about 5V now & all the others are equally low,so the 10V supply is the main suspect. ( I decided to look at the thing again today after leaving it for a few days. Pity the PSU is such a pain to remove and work on. Have most of the screws out but one refuses to move - the one holding the heatsink to the main chassis immediately under the fuse. I adjusted the grid bias with no effect on the display worthy of comment, so it is not anything to do wiith the actual fault. I am planning to replace the 10 or so electrolytics in the PSU as these are supposed to be a common problem area although I can't see any obvious damage but these are cheap enough not to worry about. I also cleaned and checked ebvery connection to the CRT just in case of a problem due to muck everyywhere but no difference to the display. I suppose that the U800 problem is usually a case of "NO DISPLAY" rather than a poor display and so assume that this is not something I need to worry about at the monent. I will keep looking as & when I can. Thanks for your help and encouragement. Must admit that I find these scopes a challenge but how satisfying when (if)I get it working. Cheers Phil. --- In TekScopes@..., "sukrat2007" <sukrat2007@...> wrote: if it cleared up your display problem? Incorrect grid bias can cause |
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Re: 2215 Problem
Garey Barrell
Stefan -
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It's not right across the line. It's in series with a 470 ohm 1/2W CC resistor (which now measures 19 ohms) and looks like a "snubber" across the AC line "after" a series inductor. There's an MOV (250VAC) and a .001 cap across the line just after the fuse on the "line" side of the inductor. This unit is rated for 220 primary power, although it's never been used on anything but 120VAC. 73, Garey - K4OAH Glen Allen, VA Stefan Trethan wrote: I'm assuming this was the x-capacitor (across the power line)? |
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Re: 2215 Problem
Stefan Trethan
I'm assuming this was the x-capacitor (across the power line)?
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If so the very same thing happened to me and a fluke 8842a. It had just come from singapure, and worked just fine for a few hours beforehand. The cap leaked a nasty brown liquid (and acrid smell). It stained my fingers for days. The cap was actually inside a Schaffner brand mains filter module. Anyway, if it was the x-capacitor, you should replace it with a rated x1 capacitor for mains filter purposes. ST On Thu, Sep 18, 2008 at 11:06 PM, Garey Barrell <k4oah@...>wrote:
I was using my 2215 for an hour or so the other night, and moved over to |
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Type 111 Pretrigger Pulse Generator not up to speed
I finally got around to replacing the caps in my Type 111 (s/n 490)
and find that it is not as fast as advertised; it's around 790pS, where i had expected <=500pS. It's true that I'm using a 1nS Tr scope (with direct 50 ohm connection) but I am back-calculating the 111's Tr from the observed 1.275nS. I twiddled the avalanche adjust knob and 790 is the best I could get, and even that was pretty twitchy. Anybody fought this battle before? Is Q84 (the output avalancher, a 2N636) just tired out from years of having to work so fast? :) |
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Re: Data transfer software for Tek 7854 ??
Geoff
I've uploaded a zip file of BasicA programs provided long ago by Tek.
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Enjoy. --Geoff --- In TekScopes@..., "nj902" <wb0emu@...> wrote:
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New file uploaded to TekScopes
Hello,
This email message is a notification to let you know that a file has been uploaded to the Files area of the TekScopes group. File : /TEK-7854 SW.zip Uploaded by : gbglacier <geoffb@...> Description : Tek-7854 Software Zip File Utilities You can access this file at the URL: To learn more about file sharing for your group, please visit: Regards, gbglacier <geoffb@...> |
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Re: Data transfer software for Tek 7854 ??
Geoff
I uploaded a Tek Document (pdf) that describes and contains the Basic
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programs to which I think you are referring. Have Fun. Geoff --- In TekScopes@..., "nj902" <wb0emu@...> wrote:
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