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Re: let's bring this back to life Re: Tektronix 453 high voltage problem
A winding can impregnated with epoxy without being potted in it. I restored my early 453 by rewinding, and it wasn't potted. See topic and photo album titled "453 HV Transformer Rewind".
Dave Wise ________________________________________ From: [email protected] <[email protected]> on behalf of william_b_noble <william_b_noble@...> Sent: Monday, June 11, 2018 11:55 AM To: [email protected] Subject: Re: [TekScopes] let's bring this back to life Re: Tektronix 453 high voltage problem The reason I don't think that the transformer epoxy is going bad is because the transformer is not potted at all. I can see the windings. My understanding is that later transformers were potted. I have the early style supply with the vacuum tubes for the 12kV high voltage doubler. |
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Re: let's bring this back to life Re: Tektronix 453 high voltage problem
The reason I don't think that the transformer epoxy is going bad is because the transformer is not potted at all. I can see the windings. My understanding is that later transformers were potted. I have the early style supply with the vacuum tubes for the 12kV high voltage doubler.
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Re: OT: Old ICs for sale
Ditto here.? I haven't had a serious bidding war on any item I've sold in years either.? I financed my hobby budget in grad school by selling old junk vacuum equipment and old Tek stuff and it used to be worthwhile to sell it.? As e-bay popularity increased, I suppose more competition grew, and also large surplus sellers came on-board, which is great for buyers, not so much for individual sellers.? Fees also increased, and for that matter, shipping is through the roof now.? ??
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But I also don't "bid" now.? I always "snipe" (with auctionsniper).? ?That lets me think about the price I think the item is "worth" and what I am willing to pay for it in a calm, rational environment.? I set the desired price and walk away.? If I get it for a low bid, great, and if I go to the maximum, at least I don't end up regretting it immediately. ? Dan On Monday, June 11, 2018, 2:14:00 PM EDT, Dave Seiter <d.seiter@...> wrote:
A bidding war hasn't happened to any of my listings for years, but yeah, it's so much fun to watch!? These days, it's usually only rare items that end up in bidding wars, but certain categories see more activity than others.? Another fun event is having two or more people snipe with "silly" bids at the last second. -Dave ? ? ? From: Dennis Tillman W7PF <dennis@...> To: [email protected] Sent: Monday, June 11, 2018 10:50 AM Subject: Re: [TekScopes] OT: Old ICs for sale ? Hi Tom, and everyone who bids on Ebay, There is some misunderstanding about prices on Ebay: Newbies and or sellers with stores frequently list their items with arbitrarily high prices. Sometimes they simply look at current listings and price accordingly. BUT what really matters is what these items SOLD for. To find that out you have to look carefully through the completed listings for the auctions that were successfully concluded. That will tell you the true price the market thinks this is worth. If there is an outlier in the completed auctions that sold for a truly outrageous price you have to look at the bidding that took place. It was probably between two newbies that didn't understand how Ebay works and they kept outbidding each other by a few dollars each time. If you are a seller you always hope your item will be bid up by newbies to absurd prices. It is lots of fun to watch one of these bidding wars take place and wonder where it will end. Dennis Tillman W7PF -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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Re: OT: Old ICs for sale
John Griessen
On 06/11/2018 12:28 PM, Dave Seiter wrote:
Selling items is better than watching TV, and if they get used, it's better than dumping them in landfillYes, I have a scale that goes to 5kg and a squirt bottle of diluted wood glue for putting laser printed labels on packages. Lots of things can go in flat rate USPS envelopes stuffed to resemble a football. First class package rate for a padded bubble mailer under a pound is a good way. It helps to be near a source of cardboard boxes. When I gather boxes from local retailers 130 feet from my door, I often get good packing material too. I use an old Canon S30 for photos because it gets good exposures and focuses well, and makes photos about 2400 pixels across -- not too large so they quickly can be fixed up in GIMP photo editing tool. Instead of cables to the camera, I remove and replace its compact flash card, (about 3 x 4 cm), and use that with a dedicated compact flash card reader. That all makes for a fairly quick round trip of photo shooting to serving up on a web site (craigslist or ebay). |
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Re: OT: Old ICs for sale
Good info - wasn't aware of those links.
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Thx Tom Best, John Justin On Mon, Jun 11, 2018 at 2:17 PM, Tom Gardner <tggzzz@...> wrote:
On 11/06/18 18:50, Dennis Tillman W7PF wrote:Hi Tom, and everyone who bids on Ebay,Indeed, but care isn't needed: just select "sold listings" :) |
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Re: OT: Old ICs for sale
On 11/06/18 18:50, Dennis Tillman W7PF wrote:
Hi Tom, and everyone who bids on Ebay,Indeed, but care isn't needed: just select "sold listings" :) There are a couple of other useful tools for buyers: ? - to find out what an "or best offer" actually sold for, use and paste in the item's number (as found buried in the URL) ? - to find out what offers a seller has accepted/rejected, use with the seller's name That will tell you the true price the market thinks this is worth.Try watching the live online auctions! Dennis Tillman W7PF-----Original Message----- |
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Re: OT: Old ICs for sale
A bidding war hasn't happened to any of my listings for years, but yeah, it's so much fun to watch!? These days, it's usually only rare items that end up in bidding wars, but certain categories see more activity than others.? Another fun event is having two or more people snipe with "silly" bids at the last second.
-Dave From: Dennis Tillman W7PF <dennis@...> To: [email protected] Sent: Monday, June 11, 2018 10:50 AM Subject: Re: [TekScopes] OT: Old ICs for sale Hi Tom, and everyone who bids on Ebay, There is some misunderstanding about prices on Ebay: Newbies and or sellers with stores frequently list their items with arbitrarily high prices. Sometimes they simply look at current listings and price accordingly. BUT what really matters is what these items SOLD for. To find that out you have to look carefully through the completed listings for the auctions that were successfully concluded. That will tell you the true price the market thinks this is worth. If there is an outlier in the completed auctions that sold for a truly outrageous price you have to look at the bidding that took place. It was probably between two newbies that didn't understand how Ebay works and they kept outbidding each other by a few dollars each time. If you are a seller you always hope your item will be bid up by newbies to absurd prices. It is lots of fun to watch one of these bidding wars take place and wonder where it will end. Dennis Tillman W7PF -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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Re: OT: Old ICs for sale
Hi Tom, and everyone who bids on Ebay,
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There is some misunderstanding about prices on Ebay: Newbies and or sellers with stores frequently list their items with arbitrarily high prices. Sometimes they simply look at current listings and price accordingly. BUT what really matters is what these items SOLD for. To find that out you have to look carefully through the completed listings for the auctions that were successfully concluded. That will tell you the true price the market thinks this is worth. If there is an outlier in the completed auctions that sold for a truly outrageous price you have to look at the bidding that took place. It was probably between two newbies that didn't understand how Ebay works and they kept outbidding each other by a few dollars each time. If you are a seller you always hope your item will be bid up by newbies to absurd prices. It is lots of fun to watch one of these bidding wars take place and wonder where it will end. Dennis Tillman W7PF -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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Re: let's bring this back to life Re: Tektronix 453 high voltage problem
Phillip Potter
Awesome attention to detail, Toby! You rock! Thanks for the link, as I was able to download it to my iPad for safe keeping. I hope this helps William, too!
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Phil, N6OMM On Jun 11, 2018, at 11:09 AM, toby@... wrote: |
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Re: OT: Old ICs for sale
That I agree with.? ?Not dumping into landfill "adds value".? Hey, I saved an RM504 from a list member here and finally found a home for it, so I understand that point!
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Dan On Monday, June 11, 2018, 1:28:24 PM EDT, Dave Seiter <d.seiter@...> wrote:
Selling items is better than watching TV, and if they get used, it's better than dumping them in landfill (or at least putting that off for a while longer). -Dave ? ? ? From: Daniel Koller via Groups.Io <kaboomdk@...> To: [email protected] Sent: Monday, June 11, 2018 9:24 AM Subject: Re: [TekScopes] OT: Old ICs for sale ? Questionable how much value there really is in those chips.? I have a similar-ish collection.? But I get paid by the hour at work, so I have to subtract the time it would take me to sort them, photograph them, package them, process the e-bay posting and receipt of change, and then mail them.? It takes much more time than any of us really account for.? ?Take off the 15% you lose to ebay/paypal fees and it's almost not worth selling them, which is basically why I don't even bother with ebay anymore.? ? And those of you who are retired.... don't say "I've got the time" because then you are under-valuing your hard-earned retirement.? Occasionally I find something that might fetch me over $100 on ebay and then I consider selling it - high value items. Dan ? ? On Monday, June 11, 2018, 3:43:23 AM EDT, Tom Gardner <tggzzz@...> wrote: On 11/06/18 05:19, G Hopper wrote: I suppose that for $55 there probably is some value in that offering even if some of the chips are dead.? I do have to chuckle since I have some of the same stuff as NOS in my parts drawers and amongst the boxes I've inherited from others.? Never really considered the possibility that any of it had value.? "There's gold in them there drawers!!!!"Perhaps more than you might think - and they don't even have to be unused. Look at the fleabay prices for "mustard capacitors" and "germanium transistor" |
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Re: OT: Old ICs for sale
Selling items is better than watching TV, and if they get used, it's better than dumping them in landfill (or at least putting that off for a while longer).
-Dave From: Daniel Koller via Groups.Io <kaboomdk@...> To: [email protected] Sent: Monday, June 11, 2018 9:24 AM Subject: Re: [TekScopes] OT: Old ICs for sale Questionable how much value there really is in those chips.? I have a similar-ish collection.? But I get paid by the hour at work, so I have to subtract the time it would take me to sort them, photograph them, package them, process the e-bay posting and receipt of change, and then mail them.? It takes much more time than any of us really account for.? ?Take off the 15% you lose to ebay/paypal fees and it's almost not worth selling them, which is basically why I don't even bother with ebay anymore.? ? And those of you who are retired.... don't say "I've got the time" because then you are under-valuing your hard-earned retirement.? Occasionally I find something that might fetch me over $100 on ebay and then I consider selling it - high value items. Dan ? ? On Monday, June 11, 2018, 3:43:23 AM EDT, Tom Gardner <tggzzz@...> wrote: On 11/06/18 05:19, G Hopper wrote: I suppose that for $55 there probably is some value in that offering even if some of the chips are dead.? I do have to chuckle since I have some of the same stuff as NOS in my parts drawers and amongst the boxes I've inherited from others.? Never really considered the possibility that any of it had value.? "There's gold in them there drawers!!!!"Perhaps more than you might think - and they don't even have to be unused. Look at the fleabay prices for "mustard capacitors" and "germanium transistor" |
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Re: Help needed with no trace no beamfinder on 465 (not b)
On Mon, Jun 11, 2018 at 04:47 am, Raymond Domp Frank wrote:
After Keith's report that he had already exchanged Q1418, I had a look into a 465 in my possession.AFAIR, at least the vertical board must be disconnected (several peltola As it turns out, possibly Q1418 can be removed without removing the vertical board, maybe sideways since there is some room between the end of that board and the 'scope's rear plate. Just not obvious how to clear Q1418 on its heat sink across the screw ends fixed to the backplate, either up or sideways. OTOH, Tek's design engineers may have done a clever job here. Raymond P.S. Keith, I know those days. I always tell myself they must be good for something... |
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Re: let's bring this back to life Re: Tektronix 453 high voltage problem
On 2018-06-11 12:21 PM, Phillip Potter wrote:
I have a late serial number 453, that seems to have a combination of boards, seemingly like yours. To your advantage, I submitted my manual for scanning, so you might want to get ahold of Toby, a member, to see where that scan is parked and then download it. It might just be the ticket for your scope...I'm so glad to hear about your rescue, William! I also obtained a 453 rescued from a potentially terrible fate. Phil's 453 manual has been digitised here: I hope this helps. --Toby Phil |
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Re: OT: Old ICs for sale
Questionable how much value there really is in those chips.? I have a similar-ish collection.? But I get paid by the hour at work, so I have to subtract the time it would take me to sort them, photograph them, package them, process the e-bay posting and receipt of change, and then mail them.? It takes much more time than any of us really account for.? ?Take off the 15% you lose to ebay/paypal fees and it's almost not worth selling them, which is basically why I don't even bother with ebay anymore.? ? And those of you who are retired.... don't say "I've got the time" because then you are under-valuing your hard-earned retirement.? Occasionally I find something that might fetch me over $100 on ebay and then I consider selling it - high value items.
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Dan On Monday, June 11, 2018, 3:43:23 AM EDT, Tom Gardner <tggzzz@...> wrote:
On 11/06/18 05:19, G Hopper wrote: I suppose that for $55 there probably is some value in that offering even if some of the chips are dead.? I do have to chuckle since I have some of the same stuff as NOS in my parts drawers and amongst the boxes I've inherited from others.? Never really considered the possibility that any of it had value.? "There's gold in them there drawers!!!!"Perhaps more than you might think - and they don't even have to be unused. Look at the fleabay prices for "mustard capacitors" and "germanium transistor" |
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Re: let's bring this back to life Re: Tektronix 453 high voltage problem
Phillip Potter
I have a late serial number 453, that seems to have a combination of boards, seemingly like yours. To your advantage, I submitted my manual for scanning, so you might want to get ahold of Toby, a member, to see where that scan is parked and then download it. It might just be the ticket for your scope...
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Phil Phil, N6OMM On Jun 10, 2018, at 11:50 PM, william_b_noble <william_b_noble@...> wrote: |
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Re: Help needed with no trace no beamfinder on 465 (not b)
Phillip Potter
Hi Keith,
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I¡¯ve chased my tail like this so many times, my back as permanently twisted. I have to sleep on my side, now! Next week will bring some clarity, and perspective, I¡¯m sure... see you then, and thanks for sharing this repair. Phil-in-CA Phil, N6OMM On Jun 11, 2018, at 9:15 AM, Keith Ostertag <stuff@...> wrote: |
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Re: let's bring this back to life Re: Tektronix 453 high voltage problem
RustySparks
Are you sure this is not the typical leaky HV transformer winding problem that seems to affect practically all the 453 series scopes and other similar models simply due to the transformer HV winding becoming leaky because of chemical changes in the epoxy used in transformer assembly over the years?
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My 453A has pretty much the same problem with HV, initially it would stop oscillating after being on for 30 minutes or so, got progressively worse after a year or so, eventually wouldn't start at all. It was through this forum that I learned what the problem was. At least one member here has corrected his by rewinding the HV transformer secondary. Pretty amazing project! -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of william_b_noble Sent: Monday, June 11, 2018 1:51 AM To: [email protected] Subject: [TekScopes] let's bring this back to life Re: Tektronix 453 high voltage problem I decided to dig into an early 453. Interestingly it does not match the schematics for the 453 or the 453A - some boards seem closer to the A, some to the earlier one - for example the Z axis board is clearly dated (C) 1965, but its layout matches the board found in the A manual (unless I'm just loosing my mind). This scope sat around for several years after I got it and never plugged it in - when I did plug it in there was initially no light on the CRT (except the scale illuminator) - as I messed with it for about an hour trying to make sure what was wrong, it fired up and showed a spot and vertical deflection, I could center it, but there was no trace. then it stopped. The HV circuit is one of those that will stop oscillating if there is an overload, so it's hard to troubleshoot, and harder without an HV probe. But it's clear that something is overloading the circuit. If I disconnect the cathode and grid bias circuits, it makes HV and powers the CRT filament just fine. I've tried all sorts of things, one at a time, and disconnecting the .015uf 3Kv capacitors by itself doesn't work, disconnecting the diode that drives the grid string does let it work, and the list goes on. I've come to the conclusion without a good way to verify it that it is most likely that at least one of those 3KV ceramic caps is leaky, and if one is bad, the others are probably not far behind, so I've ordered some. The HV diodes are also suspect, though they both seem to act like diodes at 115V (with a 10 W lightbulb as the load), I ordered some microwave oven diodes just to be on the safe side. I don't think my 1M CRT Grid Bias control is bad like was found upthread, when the power supply works, I can adjust the grid bias. But now, if the supply oscillates the current can rise to about 2.9 amps (it's fused at 2 amps) with all the loads connected. The transformer isn't potted, so I think it's probably not the issue. anyone care to offer some advise on something I could have missed? I'd like to get this scope working just to say that I did it - I have a couple of newer ones to look at next, I figured this one first, it's all discretes, how hard could that be >>> |
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Re: Help needed with no trace no beamfinder on 465 (not b)
Well... you know how sometimes you feel like you just maybe shouldn't have gotten up this morning? I'm having one of those days...
I evidently wired the substitute 2N3055 wrong and blew my the line fuse... then I began having issues with marginal meter leads and meter batteries (which have been on order)... then I blew the F1419 fuse ... So, I need to order some more fuses, and get meter batteries, and check my meter leads, but first take a break so I can remember this is supposed to be fun :-) I'll return to this repair job and this thread sometime next week. Thanks to everyone for helping, and hopefully we will work on it together again soon. Keith |
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Re: let's bring this back to life Re: Tektronix 453 high voltage problem
Ok, more info. I have no repair history, I got it for scrap price from an e-waste guy who used to sell at a,small flea market. It had a nice manual with it, but for a very different scope.
I have tested the low voltage supplies, they were all close, they are now within a millivolt of their proper value. I tested all the carbon resistors in the hv divider networks, and all but one were within tolerance, the 150k resistor in series with the grid adjust pot had dropped to 30k, so I changed it. I don't really suspect the diodes, but it pretty much has to be a leaky ceramic cap or two, or a diode, right? I also suspect some issue on the z axis board, for now, I disconnected it Thanks |
Raymond Domp Frank
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