¿ªÔÆÌåÓý

I recently acquired a TDS 3014B 'scope. It looks fine and operates as it should, except for its LAN interface. In the beginning (first half day since I got the 'scope), it could sometimes be

Hey Roger, I don't know the answer to your question regarding reading and writing the NVRAM. But I wonder why you feel you need to save and restore the NVRAM data. The calibration information for the

Dear all, I will have to replace the dallas chips (DS1486/DS1650) of my TDS684A. I have ordered the replacement kits (not fake China chip) from a source I have found in EEVBlog. While I wait, I have

In case you or someone else needs one or more: I've got hundreds of NOS 8085's (OKI) in their original rails at a few €/$/?'s each. Shipment from NL. Raymond

I was not getting anything at all on ALE. I removed and re-seated the 8085. Unlike the TTL logic chips, the pins on the processor were shiny and clean. However, since I have disconnected the A19 board

If you are not getting a TTL level pulse(s) on the ALE pin after reset, I would not bother going any further. Is the 8085 sitting in one of those POS TI sockets? Try rocking the core chips in their

As I recall I think the ACQ board and the computer board are "married" . I do not know how to arrange divorce and re-marry. If your effort does not work I would change back to the original ACQ board

Indeed, my suspicions were also heading in that direction, but its good to have another view. HOLD is connected directly to GND and I confirmed a ground connection there. READY is connected to 5V via

Hi Tony. First I want to thank you for your kindness in answering me. Both scopes show code 3000 in the POST. I have the service manual. Reading pags 5.36 and 5.37 of the manual, they tell you to

John, I think suspicions may be moving from ROM rot to a bad CPU or at least a need to clean the CPU pins. Before condemning the CPU check that the voltage swing on the clock input, pin 1, comfortably

One technique to "trap" a bad microprocessor is to have a series of jump or branch instructions surrounding a halt instruction.? If the mandatory jump or branch failed, then the processor would halt,

Chuck, thanks. I will have a look at the crystal driver. Will need to remove that board. Regarding the processor, I get what you are saying. I put the jumper in reset mode which holds the RESET line

The scope should have no problem running 24-7 with the case off and no fan. You have just found a problem to fix. Crystals that get hot have defective drivers that are hitting them with too much

Hmm, stuck the LA on it today but I see no processor cycles whatsoever. The LA has 16 channels but I have only 8 clips, so I connected the control lines only: RESET S0 S1 ALE RD WR TRAP INTR and GND

Looks good to me, and I don't have to go online to see your posts now... Jay

Chuck, John, The insight into 8085 programming wisdom is very illuminating. I am guessing that the 160-0459 ROM is mapped to $0000 and there are many HALT instructions (hex $76) scattered through the

Does anyone know of a link for the download of the Tek468.zip file, which contains the service ROM bin file? Thanks Tony

Heitor, What are the symptoms of the two scopes and what have you already identified as problems? Perhaps that would help us figure out ways we can help you. Please keep the symptoms of each scope

Harrison, Yes, but that action does not eliminate the rest of U550. There are other circuits in U550 that are powered through that same secondary winding of T550. That winding has 3 taps, so Pin 10

Roger, So I'm sending this letter from my PC rather than the phone. Wondering if this looks any better. I have seen my own letters from the phone since I send to all and thus getting a "Copy" Well