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Re: 555 restoration
Good point Morris. There are ways to tell if the hv is failing on the one beam side. You can turn out the lights in the room and check the hv rectifiers for the familiar red glow. If the hv has failed all of them could also be out. Or you can hold neon bulb close to the tubes in the hv secondary side and see if it glows.
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Re: 555 restoration
Morris Odell
AFAIK the 555 does not have the HV transformer thermal runaway problem that plagues later models. One other component that sometimes causes these symptoms is the 1 nf resonating capacitor across the HV transformer primary. Try replacing it with a 630 or 1000 volt modern cap as a starter.
Morris
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Re: WTB: 555 or 556 - will pick up
Jamie Ostrowski
Maybe I should just make my own boat-anchor and weld two of my 2 545's
together. I would have a nice huge 4 trace 30 MHz oscilloscope, redundant power supplies and Dual CRT's and almost 200 tubes! On Tue, Sep 3, 2019 at 9:47 PM Jamie Ostrowski via Groups.Io <jamie.ostrowski=gmail.com@groups.io> wrote: Yes I think you are right, John. I don't want to get carried away. It is
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Re: Tek 577 CT - Max Peak Volts / Series Resistor Knob Adjustment
Kyle Rhodes
Hi Chuck,
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Thank you for the tip -- indeed that's all it was, and I was able to remove it after some coercion. Unfortunately in messing with stuff, I also loosened the internal switch cog that handles the various resistor positions, and I think I have that shifted slightly. I am in the process of attempting to get that lined back up now. It's a pain finding the home position as it moves its range with the voltage selection. To start I couldn't select the lowest resistor (highest power) at lowest voltage, now I can't select the largest resistor at highest voltage....doh. Thanks, Kyle -- KSR Amps / Rhodes Amplification, LLC Kyle Rhodes (513) 480-2677 kyle@ksramps.com http://www.ksramps.com http://kylerhodesdesigns.com
On Tue, Sep 3, 2019 at 6:49 PM Chuck Harris <cfharris@erols.com> wrote:
This is a common problem. The grub screws cut a trench into
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Tek 7704 scopes in PDX area
Bill Higdon
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Re: WTB: 555 or 556 - will pick up
Jamie Ostrowski
Yes I think you are right, John. I don't want to get carried away. It is
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sometimes difficult coping with an addiction like this. :-)
On Tue, Sep 3, 2019 at 6:21 PM John Williams <books4you@telus.net> wrote:
I would advise proceeding with caution Jamie. It is easy to get excited
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Re: WTB: 555 or 556 - will pick up
Jamie Ostrowski
Yes, I do think the 565 is a wonderful scope. I have one of those. It only
goes up to 10 MHz whereas the 556 goes up to 50 MHz, which is where I foresee the part of the spectrum I would be working in most. I think someone will get that 565 soon. On Tue, Sep 3, 2019 at 3:28 PM Jason A. via Groups.Io <jagee228= yahoo.com@groups.io> wrote: Sorry - I should have pasted this in my last message - I hate to see it
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Re: Tektronix Microfiche Library
Bruce Atwood
Chuck has it exactly right, in this day and age a 1 TB scanning project should not be beyond the reach of this group. Just as I support Wikipedia I'd be happy to chip in a Hamilton. I would add, however, that the original fiches should be preserved. The scan files are great but in the end the originals should be kept safe. Wouldn't the Tek museum be able to store them in some reasonably safe environment?
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Re: WTB: 555 or 556 - will pick up
I would advise proceeding with caution Jamie. It is easy to get excited and rush into something like this. You don’t know that this is even complete, let alone working. The bezel is missing, what else might have been removed. The 556 has few tubes. I have received these with the tunnel diodes gone, which makes the unit junk. Many of the guts are unobtanium. Proceed carefully, the money you save can go toward a known good scope. That’s all.
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Re: 555 restoration
Richard Knoppow
Did you get the fan or fans going? If not that could be the problem. If so my guess is tired capacitors in the PS.
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On 9/3/2019 2:55 PM, Sparky99 wrote:
Hi everyone, I recently purchased a 555 - it arrived in very dusty and grubby, but has cleaned up to be in almost mint condition. Despite very clearly not being powered up for a very, very, long time (both fans were immobile ...) it more or less works in the more general sense of the word - a tribute to the quality and robustness of the engineering ! --
Richard Knoppow dickburk@ix.netcom.com WB6KBL
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Re: Tek 577 CT - Max Peak Volts / Series Resistor Knob Adjustment
Chuck Harris
This is a common problem. The grub screws cut a trench into
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the shaft when the knob is forced to go where it shouldn't, and the trench can't get past some bump on the knob... probably the grub screw, or its hole. Take a light and peek into the hole, you will see a pair of parallel tracks, I think. Remove the grub screws completely, and keep turning while lifting, and it will come off. -Chuck Harris Kyle Rhodes wrote:
I just picked up a 577, all seems to work well except the Max Peak Volts /
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Re: Tektronix Microfiche Library
Chuck Harris
Firehoses need special drinking attachments.
Do what businesses do, scan everything using an autofeed fiche scanner.... By everything, I mean everything. You are doing full sheets of fiche. The scanners can be rented, and it would only take a week working slowly. Make no determinations during this part of the process. Scanning time is expensive, disks are cheap. A collection this size would be at most a couple 1Tb. Once you have the data digitized, there are numerous ways of breaking it apart and giving it order. Mostly using script driven programs like the open source unpaper. That will take time, as you will have to label your files, write descriptions, add indexes, and crunch numbers. This is where the crowd sourcing begins. -Chuck Harris Dave Brown wrote: I concur with Dennis' description of drinking from a fire hose. The microfiche is overwhelming. I had a moment so I stopped into the museum to check out the 2465 since it was specifically mentioned. Here are the statistics on what we have at the museum.... If you have a request, send the museum an email. We will look and tell you what we have. Details are at https://vintagetek.org/printed-and-microfiche-manuals/
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Re: 555 restoration
One other thing to try. You could swap the hv oscillator tubes around. If one is failing it should move the fault to the other beam. Same with the hv regulators.
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Re: 555 restoration
Hi Julian. I would start as always by checking all the power supply voltages per the manual. But I think your problem is loss of high voltage, either because of a heat sensitive hv transformer or capacitor. You could remove the shield over the hv power supply for the beam that is failing. You might then cool that area with a fan or Freon spray. If the beam returns that might point to a component. If you have an old analog volt meter you can also measure some voltages. Be careful using a DMM though, this much voltage will eat most DMMs.
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555 restoration
Sparky99
Hi everyone, I recently purchased a 555 - it arrived in very dusty and grubby, but has cleaned up to be in almost mint condition. Despite very clearly not being powered up for a very, very, long time (both fans were immobile ...) it more or less works in the more general sense of the word - a tribute to the quality and robustness of the engineering !
There is one problem however, which is why I'm posting here. On power up, both the upper and lower beam traces are displayed with good brightness. About 3 minutes later, the upper beam fades and then disappears. Turning up the intensity temporarily brings the trace back for a few seconds, but it then permanently disappears. The lower beam is still fine. Powering the instrument off/on temporarily brings the upper beam trace back for a few seconds only, which seems to indicate that the problem is temperature related. Does anyone have any ideas where I should be looking of what the problem might be? All the best Julian
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Re: Dead CRT on 2215A . Where to start?
Bob Albert
In my case I replaced the IRF820 and it works great now.
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On Tuesday, September 3, 2019, 01:52:10 PM PDT, ulf_r_k via Groups.Io <ulf_r_k=yahoo.com@groups.io> wrote:
Regarding Leo / Satbeginners comment. After a >>Bang<<< in a 2221A scope I was advisedto use the 42V method in order to see what had gone wrong. It was indeed the primary switch regulator.But it was messy trying to figure out which oneof all semiconductors that had failed and the mechanicswas not very inviting to work with so I decided tosimply replace all of them. Cheers Ulf Kylenfall
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Re: Dead CRT on 2215A . Where to start?
ulf_r_k
Regarding Leo / Satbeginners comment.
After a >>Bang<<< in a 2221A scope I was advisedto use the 42V method in order to see what had gone wrong. It was indeed the primary switch regulator.But it was messy trying to figure out which oneof all semiconductors that had failed and the mechanicswas not very inviting to work with so I decided tosimply replace all of them. Cheers Ulf Kylenfall
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Tek 577 CT - Max Peak Volts / Series Resistor Knob Adjustment
Kyle Rhodes
I just picked up a 577, all seems to work well except the Max Peak Volts /
Series Resistor Knob needs adjustment. The outer portion of the knob with the white arrow that points to the voltage is off by one increment. i.e. It points to 25 instead of 6.5, 100 instead of 25, etc. I did the obvious and loosened (then completely removed) the two visible set screws on the inner knob. When loosened the knob will spin more or less freely, but it does not come off. This knob is spring loaded upon pull, and aside from the slippage on the shaft, it seems just as connected when pulled. I can't get it to budge, no matter what I do. I figure there's a burr on the shaft, and the knob bushing is grabbing onto it. If this is the case, I'm not sure what else to do besides pull and twist until it works its way off... In lieu of accidentally breaking any difficult to replace parts, I thought I'd reach out to the hive mind and see if anyone has any suggestions. I already looked in the service manual, and it implies the knob will come off with those two set screws loosened, allowing access to the outer knob set screws... Thanks, Kyle -- KSR Amps / Rhodes Amplification, LLC Kyle Rhodes (513) 480-2677 kyle@ksramps.com http://www.ksramps.com http://kylerhodesdesigns.com
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Re: WTB: 555 or 556 - will pick up
Sorry - I should have pasted this in my last message - I hate to see it parted out, but there's only so many of these stray scopes I can adopt... :-P
https://www.ebay.com/itm/TEKTRONIX-DUAL-BEAM-OSCILLOSCOPE-TYPE-RM-565/173848207856 Best regards, Jason
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Re: WTB: 555 or 556 - will pick up
ChuckA
Unless it is something ultra rare or I just can't live without, I walk away from getting into a bidding war. If it is a tube scavenger that he's dealing with maybe you can work out something the tube guy gets the "golden ear" tubes and you can get the scope, I've done that before.
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On 9/3/2019 4:10 PM, Jamie Ostrowski wrote:
Well I started talking to the fellow and it's actually in Florida now. :-) --
See Early TV at: www.myvintagetv.com
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