Help fixing Vector-06c

[x-code]

it doesn't respond to the resets.

That could be a clue, actually.
Does the CPU gets a proper RST signal? What happens on the address bus right after that? Do the address lines of the bootloader ROM chip get the same signals that are on the address bus?

Another place to look is whether video memory refresh works properly (as far as I recall it uses its own EEPROM to form all the right signals)

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Should they go high again after the boot ROM is copied to RAM?

The ROM is not copied to RAM (apologies for probably misleading you with an inappropriate use of the word "shadowing").
It's rather like chip select (inverted, I assume) goes low for ROM and high for RAM when the CPU is reading data and vice versa when CPU is writing data.

[cyb2600]

The reset line is low, it goes high for a second when I press the reset buttons. I see activity on the data and address busses but I haven't yet verified it's the same on the CPU as the ROM. I haven't looked at all at the video memory circuit.

Do you know what causes the "rus" light to turn off and for the buzzing to stop? Is that evidence the ROM is executing?

[x-code]

When I boot the computer up, all 4 chip selects on the ROM are high.

If those chip select inputs are inverted, that's suspicious. As it probably means that the reset schematics is faulty.
Still, if the motherboard serial number ends in something like 89-03, it could also be that you're dealing with an old revision of the motherboad, and I vaguely recall old revisions did require a manual hard reset after power on.

So - after pressing and releasing the two rightmost buttons in the upper right the chip select for the ROM chip should go low, and the CPU should start reading instructions from ROM address 0000

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Do you know what causes the "rus" light to turn off and for the buzzing to stop? Is that evidence the ROM is executing?

Actually, yes - it could mean signs of life. At least if we are to believe this guy's post: https://zx-pk.ru/threads/29199-reani...l=1#post965695

[cyb2600]

The serial number does end in 89-3. The computer does nothing but buzz until the reset buttons are pressed. The ROM seems to have 4 chip selects, two active high and two active low. The two "active high" ones are tied to +5 so they're always high. The two "active low" are high until the reset buttons are pressed, then there's data continuously on both. It seems like the CPU is executing code from the ROM. I think the problem might be with the RAM or the video circuitry.

[x-code]

If you can hook up the Vector's "tape in" to your soundcard "line out", try opening this web page:
http://sensi.org/scalar/ware/555/

then click on the ellipsis next to "test.zip" - you'll see

testtp [pack].rom 997▶
testtp.rom 1024▶

Power up the Vector, then press and release "VVOD" and "BLK" simultaneously to make sure a proper hard reset and entering the bootloader mode.

Then click on the Play button symbol next to "testtp.rom"
When the sound stops playing, the "rus" led should start flashing.

If that's the case, press and release "BLK+SBR" simultaneously - this will deactivate the bootloader and start executing the manufacturer self-test.

[cyb2600]

I powered on the Vector and see the checkerboard and hear buzzing and "rus" light is on.

I pressed "VVOD" and "BLK" simultaneously. The screen goes black, the "rus" light turns off, the buzzing stops, and I hear the relay go click.

I play the "testtp.rom" and hear the tones on the Vector06-c speaker.

When it's done playing the LED doesn't flash and the screen stays black.

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[KTSerg]

I powered on the Vector and see the checkerboard and hear buzzing and "rus" light is on.

I pressed "VVOD" and "BLK" simultaneously. The screen goes black, the "rus" light turns off, the buzzing stops, and I hear the relay go click.

I play the "testtp.rom" and hear the tones on the Vector06-c speaker.

When it's done playing the LED doesn't flash and the screen stays black.

The checkerboard, when turned on, indicates that the image is formed correctly. This is typical of Vector, which does not autostart on power-up.
But until the download grid appears, yellow on a blue background, the program from the tape recorder will not load.
There is a suspicion that the bootloader checks the memory, then detects an error and loops on this test.

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I believe one should test memory.
Since the bootloader cannot be used, there are two options: either change the bootloader microcircuit to another, into which to write the memory test; or connect an external bootloader microcircuit to the long "ВУ" connector, which is much more difficult.

[cyb2600]

Does anybody have the pinout for the р565ру6 RAM? I'm seeing some very strange signals on pins 14 and 13. I think everyone is right about the capacitors being bad.

[KTSerg]

Does anybody have the pinout for the р565ру6 RAM? I'm seeing some very strange signals on pins 14 and 13. I think everyone is right about the capacitors being bad.

http://www.asvcorp.ru/darch/electron...ru6/index.html

[CodeMaster]

Does anybody have the pinout for the р565ру6 RAM?

Datasheet