Re: Tek 494AP VR board mystery
Agreed, that is very weird. Same with those resistors... usually you try to minimize the number of BOM line items by consolidating resistors, but they seem to have done the opposite here. The LC BPF
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John Miles
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#184580
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Re: Tek 494AP VR board mystery
If it is purely a (TTL) logic section, it could be that a little diode-logic was added to save a gate package or such, and required a little different biasing to assure proper levels. Often, a Ge or
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Ed Breya
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#184579
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Re: Tektronix RAMS (Surplus) Store - Odd hours?
I got to answer my own question today, it's the 3rd Thursday of the month and I had the day off so I swung by. I found a sign next to the door that reads: RAMS Country Store is currently closed due to
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Magic_Smoke
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#184578
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Re: Tek 494AP VR board mystery
On Thu, 15 Jul 2021, Ed Breya via groups.io wrote: It is pure logic, ON/OFF. 'LS145 pin active (low), +15V forward bias, pass diodes in full conductance, those shorting to ground reverse biased i.e.
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Sergey Kubushyn
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#184577
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Re: OT: Looking for a Pentium M765 (or maybe M780 - not sure it that will work)
Thank you Jared, I've sent a pm to arrange shipping details etc.. David
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David C. Partridge
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#184576
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Re: [HP-Agilent-Keysight-equipment] OT: Looking for a Pentium M765 (or maybe M780 - not sure it that will work)
Not a dumb question, but changing the mobo in a Waverunner Xi is apparently somewhat of a challenge. It also needs to work with XP embedded. David
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David C. Partridge
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#184575
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Re: Tek 494AP VR board mystery
I don't know the circuit here, but you may want to look at the logic and PIN control circuits and circuit descriptions in more detail. Sometimes a couple extra dB attenuation or passing, depending on
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Ed Breya
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#184574
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Re: ++Processor error on TDS 754D on startup
that was supposed to be shifts and xors
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pmoyle111
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#184573
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Re: [HP-Agilent-Keysight-equipment] OT: Looking for a Pentium M765 (or maybe M780 - not sure it that will work)
This might be a dumb question, but why not get a different motherboard? <david.partridge@...> wrote:
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cheater cheater
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#184572
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Re: ++Processor error on TDS 754D on startup
That sounds like a plausible theory, all though, what you described as a crc is really a checksum. A crc is similar but much more stringent. It is a polynomial with a characteristic divisor. In
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pmoyle111
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#184571
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Re: Tek 2230 Repair and Maintenance
Bert, Jeff, and Albert, thank you for the response. Bert, I am planning on replacing the line caps. Seems to be the No.1 item to address during my research. Definitely not leaving that out! I have
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Charlie
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#184570
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Re: TM 504 Power Module Questions
I used coax but even so the environment back there is so electrically noisy that the THD measured via the backplane is significantly higher than when connected around the front with BNC cables. Beware
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EJP
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#184569
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Tek 494AP VR board mystery
Can somebody come out with any reason for the CR3068 diode on VR 2nd Filter Select board (left bottom corner on the schematic on page 185 of 494A/AP Vol.2 Service Manual)? There are 5 filters there,
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Sergey Kubushyn
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#184568
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Re: OT: Looking for a Pentium M765 (or maybe M780 - not sure it that will work)
I have the following CPU's spare if any of these will be of use: 1x SL6F9 - M705 1x SL7EG - M725 1x SL7SA - M740 2x SL7EN - M745 1x SL7V3 - M765 1x SL7VB - M780 I'm sure I could send one or two
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Jared Cabot
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#184567
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Re: OT: Looking for a Pentium M765 (or maybe M780 - not sure it that will work)
David, here is the chip data. Lots of info to be found using a search. I have several Dell desktops and HP laptops from that era but you need to state if it is a desktop board or a converted laptop.
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Bill (Doc) Courtright
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#184566
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Re: OT: Looking for a Pentium M765 (or maybe M780 - not sure it that will work)
Hi David I have 8 Pentium, 4 Pentium 3 and 2 Pentium 4. But none have a M in their markings like M765 or M780. Have a couple 1 gb 2700 and 1 3200, several 512mb of this speed. Have 5 AMD processors
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shalopt
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#184565
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Re: ++Processor error on TDS 754D on startup
Looking at what I think is going on, it's possible that the processor was in the middle of writing to NVRAM and corrupted the process.? (it's write, and then write a checksum to validate the data).?
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Harvey White
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#184564
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FIXED! Shock Mount Replacement for Type D and Type H 500-series plugins (was [TekScopes] Another interesting Tektronix web site)
FIXED! "DJI ZH3-3D Damping Rubber Set (Part 42)", less than $10 at ebay. This is four bags of four different isolators, for an RC helicopter camera mount, one of DJI¡¯s ¡°Zenmuse¡± series. The
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Dave Wise
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#184563
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Re: Members in Germany, Brussels, and the Netherlands affected by the floods
Dennis, in the affected regions is no power, no internet, no water, no food. So it will take some time to reach the people. Peter ==============
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Heinz-Peter Deutsch
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#184562
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++Processor error on TDS 754D on startup
Last winter we had a power outage where the power co would turn power on for 15 min ever hour or so. The scope was soft turned off by the front button. Since then I have been getting the error message
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pmoyle111
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#184561
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