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Re: fitting new 'sleepy eye' power indicator to 2465 'scope?
Sorry I couldn’t help more, Jon.
I have one of the Hekimian 41-01 transmission test sets here that is part of a test suite. It has 20 of those switches on it. If you decided to go the extra mile maybe someone has an old parter available but still don’t know if the switch assembly is the same as in the Tek scope. Probably not. There is one on ePay at a ridiculous price but the photos will give you an idea as to what I am talking about. All of the indicators on the switches show black (off) & green (on). Greg |
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Re: Tektronix 2247A problem. Keep or return?
Thanks again guys! The 2247A has been running overnight with signals in each channel and everything has been humming along ok, no lockups.
I'll put it on the bench sometime today or tomorrow and check the DC voltages per the service manual and check for ripple. I'll have a look at the diodes and check their marking and see what's what.. If any electrolytics require replacing, will this throw off the calibration? I don't have any of the fancy gear to do a proper calibrations (PG506A, marker generator, etc). I have a really nice 2245A and enjoy using it and always wanted a 2247A. This particular one seems to be clean and in very good condition overall. The trigger section on the 2247A seems better than my 2245A as well. The 2400 series scopes look nice but the 224x's are probably more scope than I'll ever need. I also have a nice 2232 that I like using for the DSO section. I mess around with building synthesizers and the 2232 is nice for catching really slow events. Thanks again! |
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Re: Tektronix 2247A problem. Keep or return?
On Fri, Mar 28, 2025 at 06:12 PM, VE6WMR wrote:
Jay,Comparing a 2465 to a 2247A is a bit like apples and oranges, but understood the well meaning intention to be helpful in the sense that both are old. But for one luckily the 2247A does not rely on NVRAM to store cal constants. As suggested check all voltages and ripple to make sure they are within spec. Also while you are in there, check power supply diodes, and any with ZM or ZS markings needs to be replaced as they are known to get leaky over time and cause problems. There are 17 of these diodes on the 224x (and 2252 same series) scopes power supply. Use fast diodes like MUR160 (600V 1A) or similar. Do not use common 1N400x. Also replace the 3V Lithium battery, its only meant to hold the setting of the last session, no calibration at risk. I have both 2465B and 2247A scopes, but the 47A is usually my go-to scope 95%. |
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Re: Tektronix 2247A problem. Keep or return?
It’s not unreasonable to expect that the power supply is in need of a
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recap, and a marginal power supply could cause random problems. In your shoes I’d pull the case and measure the power supplies for voltage and ripple. There’s typically a table with allowable values in the service manual. ?ann f?s., 28. mar. 2025 kl. 23:27 skrifa?i Jay Czaja via groups.io <jmczaja@...>: On Fri, Mar 28, 2025 at 09:12 PM, VE6WMR wrote:including |
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Re: fitting new 'sleepy eye' power indicator to 2465 'scope?
Thanks Greg - I got a replacement but the fine details of how this one operates does not exactly match that used in the 2465. As you say, the plastic construction is pretty delicate.
I will take another look but unless I find an easy source I think I am going to live with this. Regards, Jon N |
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Re: Tektronix 2247A problem. Keep or return?
On Fri, Mar 28, 2025 at 09:12 PM, VE6WMR wrote:
Thanks for the reply and perspective. I fully understand these are old scopes and have no problem putting in a little work to get a scope working as it should. I just get a little spooked when I can't reproduce a problem. Earlier, I turned the scope off for about an hour and started it up again and as of now the scope has been running for about 7 hours without any issues. All of the functions I've tested have been working as expected. All channels work, the display is sharp, measurements seem accurate, triggers are working well, etc. So far the only issues I encountered were the first few startups after unpacking. I have a little bit of time to decide what to do and whether to send it back or keep it. I'll play around with it for the next week or so and see if the gremlins misbehave. |
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Re: CRT's available
Hi:
Where are do you live if we want to pick them up? Walt On Thu, Mar 27, 2025 at 6:02?PM W7HPW Radio via groups.io <t265frc10= [email protected]> wrote:
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Re: Tektronix 2247A problem. Keep or return?
Jay,
I have two 2465's here, and they're known for quite a few gremlins, including NVRAM battery issues, among other problems. In my case, I have two good ones, and I can have an excellent one by parting them together and renovating. I'll cast off the remaining wreck. You can do the same with yours. It's quite an old scope, repairable, with good manuals, but far outside any warranty support. Why did you buy it then? It isn't reasonable to expect these to be without major flaws needing to be addressed. If you're ready to do that work, dive in. If you're not willing to do all that work, you should return it and buy a new overseas model with warranty. Rigol, Instek, Owon, etc. It's something like owning an older car. Much more repairable, but needing much more time into it. |
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Tektronix 2247A problem. Keep or return?
Hi folks. I recently purchased a Tek 2247A scope and upon testing it for the first time, it locked up when testing the B sweep with a msg that said
'INVALID INTERRUPT FROM 0993:F082' When I rebooted, the screen has an indecipherable error message that appears to read something along the lines of 'Part Number 100-xxxx-00' with a bunch of exclamation marks. I couldn't clearly read what the part number as it was out of focus and could get it to focus well enough to read the numbers. The 'Auto Level' and 'Auto' LEDs were flashing which indicates both a RAM and ROM problem according to the service manual. The SGL SEQ LED was also flashing but there's nothing in the service manual that mentions that LED, or at least nothing that I've found. I let the scope sit for 10 minutes and it booted back up in service mode and gave a failed battery warning, and ran through self calibration. I left the unit on and it locked up after about 10 minutes with the same error as before. After the reboot I went into the service menu and ran the self test 'until fail' and the test ran for 30 minutes without issue. I also ran through the self calibration once more. It's now been powered on for a few hours without any problems or locking up and all functions 'seem' to be working as expected. Thoughts? Would something like this be caused by a battery issue? That seems like an easy fix but if it's something deeper, I'm not sure if I'd want to chance it. Thanks! Jay |
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Re: fitting new 'sleepy eye' power indicator to 2465 'scope?
Those switches were originally made by ITT Schadow many years ago and used to be available in many styles of buttons. I’ve seen failure of the indicator several times due to the delicate plastic nature of the way it is built. Never have had to replace one in the 2465 though.
Hekimian Laboratories was known to generously use this style of ITT Schadow switches in their telecommunications test sets which can be found on ePay. Greg |
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Re: fitting new 'sleepy eye' power indicator to 2465 'scope?
Actually, I'm going to reply to my own posting...
- I have realised that getting access to the power indicator is easier than I feared - just undo the Torx screws and take the front bezel off. - It looks like the replacement part is not exactly the same as the original, and will not do the job ;-(. I'm going to give up on fixing this small fault. Regards, Jon N |
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Re: Dennis Tillman Tek 575 Curve Tracer Adapter PCB?
I can't help you on the circuit boards, but to you or anyone needing a 575 curve tracer, I want to sell mine.? I don't want to ship it.? Many other Tek items if interested.? I live not far from Chicago.? N9ESS@...? Carl
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On Friday, March 28, 2025 at 10:00:35 AM CDT, David Berlind <david@...> wrote:
Hi, I am looking for one of Dennis's PCBs and I think the one you wrote about is the one I'm looking for.? He and I were discussing it in emails a few years back and I got COVID and was down for a while and so I lost track of certain threads and projects that I was working on.? In one of his last emails to me, he noted that he had revised his paper for the Tek SCT/TubeTester build and sent me his lastest revised designs for adapting a 577 curve tracer to an EICO 677 tube tester. I have that paper and I also own both pieces of gear.? I was wondering if you still had your board or if someone else had one that I could acquire. Thank you. |
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Re: Dennis Tillman Tek 575 Curve Tracer Adapter PCB?
Hi, I am looking for one of Dennis's PCBs and I think the one you wrote about is the one I'm looking for. He and I were discussing it in emails a few years back and I got COVID and was down for a while and so I lost track of certain threads and projects that I was working on. In one of his last emails to me, he noted that he had revised his paper for the Tek SCT/TubeTester build and sent me his lastest revised designs for adapting a 577 curve tracer to an EICO 677 tube tester. I have that paper and I also own both pieces of gear. I was wondering if you still had your board or if someone else had one that I could acquire. Thank you.
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Re: What do you use as an MPS-U45 alternative?
Hi Clark.
Thanks for the replies. The reason I asked, is that I am in Brazil and shipping from the US often starts around $40. Couple that with the $20 item price, and then the 100% import tax on both item AND freight, then it would cost around $120 for those five transistors to be here, and I actually only need one. I think I'll try the TIP 102 and see what happens? At least they cost less than a single Dollar. James |
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fitting new 'sleepy eye' power indicator to 2465 'scope?
Hi All
I have a Tek 2465 which has a small fault I am hoping to repair. This is the 'sleepy eye' power indicator on the front of the 'scope. The power switch itself works fine; but the indicator shows the high-vis 'on' state even when power off. It's a small fault but I would like to sort it. I have managed to find what I think is the replacement part. I had hope it was going to be straightforward to fit it to the end of the shaft running from the front panel to the switch; but having taken the outer 'sleeve' of the 'scope off, it looks like there is going to be more work to get access than I thought. I have stripped this scope down before (I 'recapped' it a few years ago) but I have forgotten most of the order in which I need to do things. Any pointers as to what I should do next? Thanks, Jon N |
James55
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