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Tek 577 sells for $256 on eBay
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1) Availability,
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2) How deep are your pockets, 3) What do you intend to use it for -----Original Message-----<snip> One question based on your note,... given that you targeted compatibility with1) Availability, 2) How deep are your pockets, 3) What do you intend to use it for Dennis
-- Dennis Tillman W7PF TekScopes Moderator |
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Hi Craig,
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That is very disappointing. I don't understand why that would be the case. The whole point of finding a tube tester was because they are so obsolete by now people are just throwing them out. There is always at least one of them at every ham fest I go to. Also, as I wrote in my paper, most tube testers will work. On Ebay at the time I wrote this I checked for tube testers and there were over 1,000 listed. Not all would have worked but I was amazed that there were so many and I thought for sure that was a good sign there would be a reasonable chance of getting one cheaply. Dennis -----Original Message-----in his thoroughly excellent paper, that a suitable tube tester could be -- Dennis Tillman W7PF TekScopes Moderator |
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I was stunned at the complexity of the amplifier in the 577. It is extremely sophisticated, fully differential, modulated and demodulated and I recall trying to troubleshoot it in vain. I was extremely impressed with what had been done here. Not being the designer I had no idea what problems it was required to deal with but they must have been formidable.
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Another goal the 577 had was to be profitable. The 576 was extremely expensive to manufacture. The 577 was designed to fix that problem and it did. When I was trying to decide between the 576 and the 577 I happened to be in Deane Kidd's basement lab when I saw he had a 577 so I asked him which was the better curve trace. He said the 577 was his preferred curve tracer. That was good enough for me. When I discovered the 577 storage model I knew for sure that was what I had to have. I like all the othere things the 577 can do such as test analog ICs, voltage regulators, SCRs. It is very versatile. But the 576 High Current Fixture is unique to the 576. And the 576 is much prettier to look at in my opinion. You really need to have one of each with all the fixtures so you can test anything :) Dennis Tillman W7PF -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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Craig Sawyers
Hi Craig,checked for tube testers and there were over 1,000 listed. Not all would have worked but I was amazed thatthere were so many and I thought for sure that was a good sign there would be a reasonable chance ofWow - 1000! In the whole of Europe there are 15 listed as shippable to the UK. And they sell for anything (looking at completed listings) between (converting to USD) anything between $160 and $2000. Not counting shipping. |
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Dennis, there's no need to be stunned by the complexity of the 577 amplifier.
It is quite complicated, but the reason is simple. The 577 senses true DUT collector current on the high-side, right from the collector supply, so the front-end has to ride on that common-mode voltage (up to 1600V or so), hence the need for an isolation system. The 576 senses DUT current at ground level, into the emitter port, and compensates for the base and common-mode leakage currents in its rather complex bottom-side sensing, signal routing, and anti-looping system. There are pluses and minuses to each method, but both essentially get the same job done. As far as preferences go, I have both kinds, and prefer the 576, mainly because of its nicer user interface and readout. I have often contemplated adding on-screen readout to the 577, just for fun, using a 7000 series RO board system and modifying the deflection amplifiers. The big problem though, is getting the RO info from the CT circuits - all the appropriate function and range switch positions would have to be detected and decoded, from guts that were not designed for this. A large part of the 576's complexity (and cost) is all the stuff associated with the RO, designed in from the start. Ed |
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Hi Dennis,
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I'm afraid Craig is right, the prices over this side are crazy. Partly I suspect because there are far fewer around but mostly because prices on everything are way higher. Having read your paper I've been looking out for a 667 and while rare they are around over here now and again but typically equivalent of 400-500 bucks, as Craig says. I just got one from the US for ~300 inc shipping etc. Nearly all the stuff I have here I've bought from the US, even with shipping it's cheaper (and available) a lot is used in my business so I can claim the import VAT back which makes it possible, without that it would not be. The UK government charges VAT (sort of a sales tax) at 20% on the purchase price in $ converted at the rate that day+shipping+import duty (~6%). When I lived in Seattle (well, Mill Creek nr Everett actually) I was told the sales tax at 6% 'was one of the highest' in the states, and gas broke the $3/gallon price while I was there and folk were horrified! I cheered them up by pointing out we pay 20% sales tax and (at that time) ~$1.55/Litre for gas in the UK! On 5/16/2018 4:47 PM, Dennis Tillman W7PF wrote:
That is very disappointing. I don't understand why that would be the case. |
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tom jobe
My opinion is you should buy it if you have any interest in owning a curve tracer, as that is a very good deal!
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tom jobe... On 5/22/2018 5:39 PM, David Berlind wrote:
I believe I may have an opportunity to acquire a 577 D2 for $200 if anyone has an opinion on that. |
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get it!
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搁别苍é别 On 2018-05-22 05:39 PM, David Berlind wrote:
I believe I may have an opportunity to acquire a 577 D2 for $200 if anyone has an opinion on that. |
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Good Day,
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I'd agree here. Valuetronics is still asking 3,000 USD for a *576*, see Cheers, Magnus On 23/05/2018 07:16, Craig Sawyers wrote:
I believe I may have an opportunity to acquire a 577 D2 for $200 if anyone has an opinion on that.Bargain |
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OK. I am exchanging email with the seller in an effort to determine it's operational state. Just want to double check on that because I have such a pile of things that need fixing that if I bring another thing in that needs fixing, my better half is going to relegate me to the dog house.
@dennisT ... how much are you charging for your attachment and are their any other requirements I should know of? |
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This is quite an old thread, and I'm unable to find the original, which is even older.
I'd love to buy one of Dennis's boards. Is anyone selling them? I've read his Oct. 2019, v1.04 paper on the tube tester-to-curve tracer adapter. It sounds fascinating. I have an Eico 666 that I think I could use for this. I have a Tek 577 on the way that's described as being in perfect working order. It'll need a once-over, but assuming the seller is an honest Joe, my hopes are high. I certainly can use the 577 for other things as well, but matching tubes is very high on my list of things I'd like to do with it. Any info on where this project stands is much appreciated! Thanks in advance for any info. Ryan |
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I'd like to build Dennis' design also. I do have one of his PCBs. His paper
lists the Eico 665 and 667 as vacuum tube testers that have been tested to work. I found it odd that the 666 is *not* listed in his paper at all, even in the "Should Work Just Fine" list. I would be interested to know if anyone has successfully built the VTCT using an Eico 666. DaveD KC0WJN On Sat, Mar 15, 2025 at 09:01 ryanhart via groups.io <ryanhart= [email protected]> wrote: This is quite an old thread, and I'm unable to find the original, which is |
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Dave,
The difference between the Eico 666 and 667 was purely to update the types of tubes tested: the 667 added support for 9 pin Novar and 12 pin Compactron tubes, and dropped the sockets for large pin pre-war tubes. The test methodology remained the same - the 666 should work just fine as long as it has the sockets you need. Good luck - Kurt |
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Thank you for that information. That means that we can add the 666 to
Dennis' list of tube testers that will work with his VCTC. DaveD KC0WJN On Sun, Mar 16, 2025 at 13:09 Kurt Swanson via groups.io <kurt2135= [email protected]> wrote: Dave, |
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