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TroubleShooting Some TM500 gear.
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Dave
Hello everyone:
Been long over due so, First lest me say what a awesome group this is, a several members have really helped me out a lot over the years. I have been able to help several members with parts, and have offered some advice on rare occasions when able. I'm a 56year 0ld disabled, retired maintenance mechanic. I joined the group around 2000 when I bought a 2246, and in Feb., 2002 I had a hemorrhagic stroke on my left side, leaving my left hand and arm pretty much useless, a bad reaction to a blood pressure medication Cartizem, and a few years later was diagnosed with CML Leukemia. Think I was over radiated from CT scans, but try to prove it! Two of my chromosomes switched places altering my DNA and breaking the switch that tells my body to stop making white blood cells. Fortunately they are really making some tremendous strides in treating Leukemia, and have come up with some true miracle drugs for treating Leukemia, although no cure, people are living beyond 20 years with it, however the medication I take Gleevec is 2700.00 per month for life! with my stroke meds, Medicare and Medicaid shell out about 5 Grand a month to keep me going. who knows for how long? Anyway the stroke was a Blessing, when working, first in sheet metal fab, later in high stress maintenance, but always in the dwindling manufacturing field, I struggled every day to keep working, and keep a roof over my head, often unable to find work for long periods. When I had the stroke,and was recovering I meet my first and only wife a Filipino caregiver and in getting my Social security, I had the first stable income, I had ever known, my life had tremendously improved to say the least, IF I can make it to 75,I'll be happy. I still do what I love Tinkering and fixing Tektronix gear. except for a year spent in rehab, learning to walk again, been at it ever since, as a hobby in my leisure. Sorry about the long intro, but tired of explaining my situation to everyone, I meet in the group. Recently I traded a couple extra TM500 modules with a friend in the group, I got a DC504 and AM503 in the trade. Out of 25 slots available to me I randomly picked slot 3 of a newer looking TM 506 I have, for convenience sake, In hindsight, I recall I plugged in a few modules when I got it years ago, they all lite up so i assumed everything was good with it, years later when I plugged in the DC 504 I got, It promptly blew out a couple tantalums on the negative 12.5 volt rail, Thinking it was a Fluke, just went about fixing it, when I went to test it plugged in my homemade extender backwards accidentally causing a great deal of damage, hearing of this, and feeling bad for me, my friend sent a second DC504 and some other goodies, all the while I was troubleshooting the first one, by the way he checked both were working before they were sent. So we figured something in my TM506 was blowing modules, never hearing of this before, just assuming a bad slot would just go dead. Later thinking about it, what could make a module blow, possibly a blown rectifier, or a shorted pass transistor, was about all i could think of, my friend told me that a open transistor made a FG504 blow a transistor, So looking at the schematic of the TM506 and DC504 I'm thinking the Tantalumes blew on the -12.5 volt rail so the problem appears to be a bad PNP pass transistor. Doing a Google search turned up a problem another member had finding a replacement for the SJE 925, I have a MJE2955 that looks like it might work as a replacement. Can anyone confirm this or offer any suggestions? Thanks Much! Regards Dave N9OOQ |
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Alexandre Souza - Listas
Doing a Google search turned up a problem another member had finding a replacement for the SJE 925, I have >a MJE2955 that looks like it might work as a replacement.Hi there Dave! I believe you CANNOT PLUG ANYTING into a TM-50x mainframe before checking it. BTW, I think I can create a small tool that you plug in each slot and tests everything (transistors, etc). There is a test-plug-in schematic by Tektronix, but I could live with something smaller. I don't remember the exact replacement for the transistor, I BELIEVE the MJE2955 is the "used" one. Hope you get well! Greetings from Brazil and 73, Alexandre Souza, PU1BZZ |
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开云体育Alexandre,I would be interested in having a copy of that schematic. Would it be possible to post a copy? Cheers, DaveD On 2/20/2013 12:21 PM, Alexandre Souza
- Listas wrote:
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g_kupka
I am interested in a copy too.
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Thank you. Gerhard --- In TekScopes@..., Dave Daniel <kc0wjn@...> wrote:
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Except for the pinout, the MJE2955 is a fine replacement for the
SJE925. There is a non-exhaustive list and discussion of substitutes here: On Wed, 20 Feb 2013 19:09:43 -0000, "Dave" <daven9ooq@...> wrote: Later thinking about it, what could make a module blow, possibly a blown rectifier, or a shorted pass transistor, was about all i could think of, my friend told me that a open transistor made a FG504 blow a transistor, So looking at the schematic of the TM506 and DC504 I'm thinking the Tantalumes blew on the -12.5 volt rail so the problem appears to be a bad PNP pass transistor. |
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On Wed, 20 Feb 2013 16:27:36 -0300, "Alexandre Souza - Listas"
<pu1bzz.listas@...> wrote: I had more luck with this link which I suspect is the same thing:I would be interested in having a copy of that schematic. Would it beLet me try to find it! |
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Alexandre Souza - Listas
Yep, it is!
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--- Enviado do meu Motorola PT550 Meu site: ----- Original Message -----
From: "David" <davidwhess@...> To: <TekScopes@...> Sent: Wednesday, February 20, 2013 4:36 PM Subject: Re: [TekScopes] TroubleShooting Some TM500 gear. On Wed, 20 Feb 2013 16:27:36 -0300, "Alexandre Souza - Listas" <pu1bzz.listas@...> wrote: I had more luck with this link which I suspect is the same thing:I would be interested in having a copy of that schematic. Would it beLet me try to find it! |
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Kenneth G. Gordon
On 20 Feb 2013 at 16:27, Alexandre Souza - Listas wrote:
That link returns a "The file link that you requested is not valid. " errorI would be interested in having a copy of that schematic. Would itLet me try to find it! message. I would like to have that schematic also so I can fix and use my TM-500 gear. Thanks, Ken Gordon W7EKB |
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It's an obvious idea, but instead of building a test jig into a "blank"?plug-in
(which is probably going to be nearly impossible to find) you could build it seperately and connect it using the plug available for the extension adapter kit. I believe there are measurement points marked on the extension edge connector. (Not that it helps much because that is up in the TM500 frame.) Jim |
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开云体育That is exactly how I test them I made a plug from one of the extender
cards available from the video game service?people. I brought out all six
leads for the outboard power transistors so I can test them on the curve
tracer.
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I also brought out the supplies to some load resistors so I can check
voltage and ripple on each slot.
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Regards,
Tom
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David Nushardt
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--- In TekScopes@..., "Alexandre Souza - Listas" <pu1bzz.listas@...> wrote:
I would be interested in having a copy of that schematic. Would it beLet me try to find it! I tried that link and it returned a "The file link that you requested is not valid." error. For others who ran into the same problem, the file is already available on Didier's manual site at Cheers, Dave M |
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John Griessen
On 02/20/2013 02:44 PM, Tom Miller wrote:
That is exactly how I test them I made a plug from one of the extender cards available from the video game service people. I I have plenty of TM500 cards for sale as kits, but I will also sell a card set, no connector, to make a plug with, no wires, shipped in a flat envelope for $13. John |
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开云体育I might add that your cards are much higher quality than the ones from the
arcade guys.
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Regards,
Tom
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Mark Wendt (Contractor)
开云体育I'm with Tom.? I ordered the arcade
cards first, then got two sets each of the TM500 and 7000
extenders from John.? Much, much better IMO.
Mark On 2/20/2013 10:23 PM, Tom Miller wrote:
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开云体育I purchased two TM500 extenders and four 7K extenders from John. I am building the TM500 extenders now. The PWBs are of very good quality and John has done a very good job with supplying the kits. If you need an extender for either of these instrument types, I'd recommend that you get in on the next buy, assuming John does another.Cheers, DaveD ? On 2/21/2013 6:20 AM, Mark Wendt
(Contractor) wrote:
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David Hess