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Re: Replacement to DS1230AB Lithium backed NVRAM
John Miles
Well, what fun would it be otherwise? Heh...
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Would be nice if someone could X-ray one of those puppies to determine where the cell actually is. But the equivalent part numbers are even more useful; thanks for posting those. -- john, KE5FX -----Original Message----- |
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Re: Tek 528 Waveform monitor, what is it?
On Mon, Feb 05, 2007 at 06:41:41PM -0000, mmoss111 wrote:
This appears to be true with respect to all NTSC test equipment.Remember that cable will no doubt continue to supply NTSC VSB-AM TV for some time into the future in many markets. Too many retro folks don't have ATSC or QAM capability and many of those folks will happily expect their NTSC TVs to work on channel 3/4 AM VSB RF from somewhere for many years yet - maybe until it dies of old age in 15-20 years. These days only a rather small minority of households get their TV off the air - cable/satellite penetration is well over 85% in most places. So the shutdown of OTA NTSC in 2009 won't impact much. Of course compared to well tuned ATSC HDTV, the image quality on this old technology is PRETTY bad, but for many people they either don't notice or think that digital LCD/plasma is STILL way too expensive for mere TV... And downressing 720p or 1080i to NTSC can be done in a couple of chips these days... (though the 16:9 issue is a PAIN). -- Dave Emery N1PRE, die@... DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." |
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First post - Hello and a question
Hi everyone,
This is my first post to this group. I build DIY audio for myself and the more I read/talk to individuals it seems like an Oscope should definitely be on my list of things to purchase. Honestly, I can't tell you why I would need a 4-channel vs. a 2-channel scope other than 4 is greater than 2. But I would be interested in your comments. I am interested in the 2465B but it seems like prices range from $150 - $1200. If someone can point me in the right direction, I would really appreciate it. BTW, I'm guessing that all of you would recommend that buying an Oscope from eBay (as my first Oscope) would not be recommended. :) Please let me know if you disagree. Also, my budget is between $200-$300. TIA Stephen |
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Re: Tek 528 Waveform monitor, what is it?
REX ATHEY
From: mmoss111
To: TekScopes@... Sent: Monday, February 05, 2007 1:41 PM Subject: [TekScopes] Re: Tek 528 Waveform monitor, what is it? This appears to be true with respect to all NTSC test equipment. I have a ton of signal generators and various NTSC monitors and I wonder what they will be worth soon with digital TV coming? Kinda like my 8-track test tapes and now even my VCR test equipment is getting a lot less use (almost none). My whole shop will be worthless soon!! Boo-hoo..... . Our station just moved into it's new all digital facility and there is still a good bit of the analog stuff that we brought over from our old facility. I hoping they let us go through the old place soon and salvage lots of goodies. NTSC analog probably won't dissappear completely because there is so much of it around and a few of us engineers still left that want the stuff (and use it). There's a guy in Nevada that has "Quadraplex Park" which is a whole bunch of 2" video tape machines which he restored and has working in excellent condition. Right now I'm looking for an extender card for a 1410 NTSC generator (and 1410 generators and parts for that matter). I just got another one of these from Oregon and should be getting another one soon (old building, I hope). WE used to have one, but someone apparently borrowed it and didn't put it back in it's pouch in the service manual. Learned a lot from this machine and still learning a lot more. Rex |
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Re: Replacement to DS1230AB Lithium backed NVRAM
Be very careful here. There's a reason the Postal Service will not
even ship Lithium cells and it is illegal to ship them via air cargo. If you happen to dremel into the cell, not only are you getting the caustic material flung all over, the cell will most likely short- circuit when it is cut into. Lithium cells can start fires if they are shorted. ST has equivalents to the DS devices used in both the 2465B and the 243X/40. The ST devices are slightly lower priced. ST Micro 8Kx8 DS1225AB equiv. M48Z58Y-70PC1 ST Micro 32Kx8 DS1230 (DS1235) equiv. M48Z35Y-70PC1 --Victor --- In TekScopes@..., "John Miles" <jmiles@...> wrote: Is it practical towith an outboard cell? |
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Re: 3S76 Between samples settling time
aobp11
Yes there is compensation circuitry, but this is mainly before the
gate and not adjustable. I measured the bridge signals at the + and - nodes with 600mV SW input and no triggering (and shunt resistor accross Miller cap to keep the bridge at neutral position). At the suspect Ch. A over 10mV spikes appeared, at the Ch. B maybe 2mV. I interchanged the input side diode pairs between channels and the result was the signals also changed from channel. Also the "slope" problem of Ch. A was nearly cured now (total effect about 2mV of 600mV step), the same is in my other 3S76. So it seems that one diode pair has rather high capacitance while reverse biased (it's not DC leakage). Though the pairs have the same and correct GaAs colour dots, their shapes are a bit different. Could be one pair is not original. In the meantime one of the nuvistor sides diodes of Ch. B died (has too high forward voltage now)... I also found over 10mV DC accross the plugin ground connection (from connector pin 9 and soldering tag to chassis) due to bad contact between tag+srew and chassis. (There is a relatively large net current flowing there because of DC filament heating.) Moreover the 3 securing screws in the back plate were loose. This seems all unrelated to the "slope" problem but explained some of the instabilities I noticed before. Albert --- In TekScopes@..., "jvanderwall1941" <jvanderwall1941@...> wrote: the scope designers call "blow-by", their name for those components ofa signal that can pass through a sampling gate between strobes. Thisis of course limited to quite low frequencies, so a step will show upshould be covered in the manual, as there may be one or more adjustmentsto cancel it.----> > Another unrelated problem: one channel of one 3S76 has prognostic tracetalents! With one or more square wave steps on the screen, the Consistentlyclearly slopes down or up a bit even *before* the step. but Iduring about 0.3-0.4 us. I did not yet try to find the cause, thishave my opinions about this and I'm curious to read comments on feature. |
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Re: old fashioned 535 - first start after 35 years
Stan and Patricia Griffiths
Hi Michael,
If the relay is opening again after closing, it is not getting coil voltage from its own contacts. If you burnish (clean) the relay contacts, it will probably hold in until the power switch is turned off. It is not usually necessary to check the +8650 volts on the CRT anode. If the -1350 is present, then the +8650 will be OK. All of the other power supplies must be working properly before you bother to measure the -1350. The other supplies are: -150, +100, +225, +350, and +500. Stan _____ From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Michael Petereit Sent: Monday, February 05, 2007 8:19 AM To: m38a1_1962 Cc: TekScopes@... Subject: Re: [TekScopes] Re: old fashioned 535 - first start after 35 years I tried again. Since the CRT is completely covered I cannot see any filament working. Shortly before the tube's diameter gets wider some connectors for deflection I guess. Even there some color avoid having a look onto any filament. Is it really colour or might it be dirt ? The tube is such long you can't have a look from the back unless you remove the backcover. But I would like to avoid as much disassembling as possible unless it worked once. Then any other cleaning will happen and I try to "renovate" the item. I'll try to get a high voltage adapter for my Gossen multimeter. Then I'll check the -1350V and the 8960V. br, Michael m38a1_1962 said the following on 05.02.2007 03:35: <mailto:TekScopes%40yahoogroups.com>, Artek Media <manuals@...> wrote: |
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Re: old fashioned 535 - first start after 35 years
aobp11
Be careful, the CRT heater gets its supply directly from the big
mains power transformer, *not* from the HV transformer. When the isolation is bad then the HV won't start. See many earlier posts about CRT filament or heater problems. Albert --- In TekScopes@..., Michael Petereit <michael.petereit@...> wrote: any filament.you remove the backcover. But I would like to avoid as muchdisassembling as possible unless it worked once. Then any other cleaning willhappen and I try to "renovate" the item.Then I'll check the -1350V and the 8960V.---- If the voltages are all in tolerance, look at the theirhigh voltage rectifier tubes under the top HV cover to see if glowing.filaments are glowing. This will tell you if the HV oscillator is ----- No, according to 535-545 manual the CRT filament gets 6.3V from the mains transformer. Albert |
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Re: Tek 492 SA experts, can you answer these questions?
Stan and Patricia Griffiths
Hi Chris,
I used to demo the 492 as a "receiver that looks like a scope". This made it much easier for the average person who was not familiar with spectrum analyzers to quickly grasp how it worked. I used the video output to drive a Radio Shack telephone amplifier by plugging the video out directly into the suction cup microphone input on the amp and I think the levels are just fine. The Radio Shack telephone amp is powered by a 9 volt battery so it is portable and cheap. Use zero span and slope detection for FM signals and peak detection for AM signals. At shows where I was exhibiting more than one spectrum analyzer, the 492 provided the audio for a TV signal and the 2710 provided the video. For those of you who may not know, you can actually get a TV picture to display on the screen of a 2710 spectrum analyzer. The biggest complaint about this was that it was not in "color". My response was that "green is a color". Stan _____ From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Chris Johnson Sent: Sunday, February 04, 2007 12:06 PM To: TekScopes@... Subject: [TekScopes] Tek 492 SA experts, can you answer these questions? I'm learning my way around the 492 and don't yet have manuals for it. (I'd rather get print manuals than a CD copy...got a set for sale?) I'd like to be able to use the 492 as a receiver for AM and FM transmissions, to be able to hear them. My 492 has options 1,2, and 3, so the only IF option I have to work with is the 10 MHz IF output. I need to know what are the output specs for the IF output, so I can determine how much gain I'm going to need. I plan to preamplify the IF output, feed it through a detector/demodulator, and then need to add more gain to bring it up to a level suitable for further processing, including audio band filtering and level adjustment. I would PRESUME that the correct mode to run in will be zero span, is this right? Not having actually used an analyzer in this application before, I'd appreciate it if anyone could give me a how-to guide on the setup and configuration of the analyzer and outboard equipment. If I'm wrong about how to do it, I'd rather know before I get started. CJ |
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Re: old fashioned 535 -/ 541
I picked up a cheap 541 last week which worked, but not very well. The fan had broken free from it's mounts and was sitting on the chassis- I had to beg the guy I bought it from to please turn it off, I didn't really need further demo. It turned out that all the DC supplies were at least 20% low. I was surprised that it worked as well as it did! I adjusted the -150 back to where it is supposed to be (and the triggering vastly improved), but none of the other supplies changed at all. Is that normal? Even if the other supplies have their own problems, shouldn't they be traking the -150 to some degree? After about 5 power cycles the relay has stopped working, but the tube looks ok. I've had to manually engage the other relay (after warmup time). Everything in the back of the scope is really grungy with possible long term hi temp. It looks like had a long life, but the CRT is in great shape (light blue trace/phosphor). It was used for testing heads at Ampex.
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-Dave -------------- Original message --------------
From: Michael Petereit <michael.petereit@...> I tried again. Since the CRT is completely covered I cannot see any filament working. Shortly before the tube's diameter gets wider some connectors for deflection I guess. Even there some color avoid having a look onto any filament. Is it really colour or might it be dirt ? The tube is such long you can't have a look from the back unless you remove the backcover. But I would like to avoid as much disassembling as possible unless it worked once. Then any other cleaning will happen and I try to "renovate" the item. I'll try to get a high voltage adapter for my Gossen multimeter. Then I'll check the -1350V and the 8960V. br, Michael m38a1_1962 said the following on 05.02.2007 03:35:
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Re: Tek 528 Waveform monitor, what is it?
This appears to be true with respect to all NTSC test equipment.
I have a ton of signal generators and various NTSC monitors and I wonder what they will be worth soon with digital TV coming? Kinda like my 8-track test tapes and now even my VCR test equipment is getting a lot less use (almost none). My whole shop will be worthless soon!! Boo-hoo..... |
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Re: SC 501 sync
Jerry Massengale
Greg,
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Thanks for your good suggestion. The signal at the input of the trigger generator looked great and I assumed the balance circuits was okay. I checked the adjustment for trigger balance and found that the junction of r200/c200 was at -3V rather than +65mv. I adjusted for the +65mv and it syncs very good now. I should have checked the external sync too. Thanks for your good help. Jerry Greg_A <greg.a@...> wrote: Jerry hi, I looked for you schematics and I think you could concentrate on signal flow from Q184, Q190 up until U200 pin #15 - that should be trigger in for that chip. Greg At 07:13 AM 2/4/07 -0800, you wrote:
Greetings, I have an SC501 that has poor sync. The unit works better at Usec settings than Millisec settings. I can swap U200 with a unit that works good and see no improvement. I can set 2 units side by side on extenders and compare voltages and waveforms and not see anything suspicously different between the two. One is stable and locked, the other is very, very, close but not stable. When the sync on the bad unit is at it's most stable point, the blanking output slows dramatically and the screen flickers. The power supply voltages are good with no apparent ripple. The Msec timing cap, C230 measures the same on both units(0.987uf and 1.02uf). I am attaching the schematic for the U200 circuit. Suggestions are welcome. I would love to see a datasheet for U200. It is a Tektronix made IC, pn 0155-0055-00. Jerry |
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Re: old fashioned 535 - first start after 35 years
Michael Petereit
I tried again. Since the CRT is completely covered I cannot see any
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filament working. Shortly before the tube's diameter gets wider some connectors for deflection I guess. Even there some color avoid having a look onto any filament. Is it really colour or might it be dirt ? The tube is such long you can't have a look from the back unless you remove the backcover. But I would like to avoid as much disassembling as possible unless it worked once. Then any other cleaning will happen and I try to "renovate" the item. I'll try to get a high voltage adapter for my Gossen multimeter. Then I'll check the -1350V and the 8960V. br, Michael m38a1_1962 said the following on 05.02.2007 03:35:
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Re: old fashioned 535 - first start after 35 years
Richard Aston
The delay relay closes its contacts which energises the coil of a conventional relay which a: shunts the contacts of the delay relay, thus maintaining itself closed and b: disconnects the heater supply to the delay relay which allows it to cool so that it may be ready to provide another delay if the power is interrupted.
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The delay relay therefore drops out of circuit immediately it closes. It should not drop out with a 'big spark' thirty seconds later. Richard. casej451 wrote: As far as I know there is only one delay relay. It kicks in after |
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Re: 7D02 Logic Analyzer
Kuba Ober
On Saturday 03 February 2007 00:37, you wrote:
I have a Tektronix 7603 mainframe, with a 7D02 logic analyzer plugin.I know nothing about it, but here's a hint: the 7D02 will surely have some software in the personality module -- probably the disassembler or dissassembly tables, etc. I don't know whether there is any software in the main unit or not. I'd assume there should be *some*. Anyway, this doesn't look too right. If you have the manual, I'd suggest to start troubleshooting it per the manual. The manual should also tell you what's the expected behaviour w/o the PM. If you need the manual, let me know off list. Cheers, Kuba |
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Re: old fashioned 535 - first start after 35 years
As far as I know there is only one delay relay. It kicks in after
the tubes have had a chance to warm. The only time mine ever kicked out was when the thermal protection tripped, which it will do fairly quickly without the fan, with the cover off. Check the regulated voltages of the low voltage power supply. That is very important. Everything is referenced off the -150v supply. There are some .01 capacitors across the precision voltage dividers that probably leak badly. And speaking of capacitors, these scopes were originally full of Sprague "black beauty" paper capacitors. They will be black plastic things with a solder blob at one end. All of them should be replaced. The 535 uses a high voltage tripler made of 3 tubes. The capacitors which charge to make the high voltage were probably originally black beauties. If they are still there they are surely bad. John |
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Re: old fashioned 535 - first start after 35 years
faustian.spirit
--- In TekScopes@..., "Petrosilius Zwackelmann"
<michael.petereit@...> wrote: so far but try what you suggested. start after around 1 minute a relais was working i the back, below the big fan. After another 30 sec the relais release with a big spark. I don't think it should release until you switch off the power. This must be the relay which switches on the anode voltages after the tubes are at working temperature. BTW does somebody know how many different thermal delay tubes there are? but do not relase the contact any more. I assume some capacitors might be charged to high and keep voltage. out . startIt may be as far back as two years ago but there was a lot ofdiscussion. be outtracing the circuits for bad electrolytic.. Many will suggest that --of business till you find a doaner scope |
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Re: old fashioned 535 - first start after 35 years
Dave,
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I fond that thread but it didn't gave that conclusion. I used alcohol for slight mud, this scope was placed in a dirty an humid cellar for years without it's coverage. The aluminium is best cleaned by caustic potash but it will eat up tin too. Thus I tried with a industrial cleaner which worked pretty good. In the area of the high voltage transformator I didn't used anything else than alcohol. I was afraid of getting shorts by using chemical stuff. I try to build up ths voltage divider to measure the high voltage. BR, Michael -------- Original-Nachricht -------- Datum: Sun, 04 Feb 2007 14:27:26 -0600 Von: Artek Media <manuals@...> An: Michael Petereit <michael.petereit@...>, TekScopes@... CC: Betreff: Re: [Tekscopes] old fashioned 535 - first start after 35 years Michael --
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Re: old fashioned 535 - first start after 35 years
Petrosilius Zwackelmann
Well, all tubes below the CRT are working. I didn't checked the CRT so far but try what you suggested.
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Btw: The startup behaviour of the scope is strange. On the first start after around 1 minute a relais was working i the back, below the big fan. After another 30 sec the relais release with a big spark. Now the startup is different. The relais is working after 30 seconds but do not relase the contact any more. I assume some capacitors might be charged to high and keep voltage. I'll try agai once I'm back home tonight. BR, Michael -------- Original-Nachricht -------- Datum: Mon, 05 Feb 2007 02:35:04 -0000 Von: "m38a1_1962" <m38a1_1962@...> An: TekScopes@... CC: Betreff: [TekScopes] Re: old fashioned 535 - first start after 35 years Before you go too far with the chassis cleaning and wholesale tube --
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Marvin Moss
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