Tandy 6000 HD: No system

[NeXT]

We have one 6000 HD that hangs around the shop doing nothing and I want to see what's on the drive however the system is unresponsive.
I have already confirmed that the power supply and the screen at least are good and have reseated all the chips in the system and even tried to power the system on with all the additional cards removed so it's pretty much just a TRS-80 Model II and I get nothing at all. Not even a prompt to insert a disk.
I'm not sure what might be up.

 

[Druid6900]

I'll assume you've done all the standard things, checked the CRT neck for heater glow, adjusted the external brightness and contrast controls, check for static charge on the face of the CRT, things like that. Any hard drive or floppy drive activity when it powers up? Keyboard light activity?

 

[NeXT]

While testing another Tandy 6000 before I sold it and shipped it off I actually made an extension cable so that I could feed the tube a video signal from the known working system. The display works fine. It just isn't getting a signal from the board.
I also swapped out all the boards with known working ones and still no dice.
The floppy drive busy light very briefly blinks at power-up but that's to be expected and aside from spinning up the hard drive does nothing, probably because it's waiting for the system to make it do something.
Short of the main logic board itself which looks spotless I have pretty much tested every component in he system and they all work.
There's this itch in the back of my brain telling me that the ROMs have gone bad which means I'm screwed as I have no way to burn new ones.

 

[Druid6900]

It's possible, but, in all the years I've been a computer repair technician and all the machines of any age I've worked on, I've never had to replace a ROM in/on anything.

Have you tested the RAM on the motherboard?

 

[NeXT]

No. I have not tested the ram as I do not know how exactly the ram works in a Model II/12/6000. I had issues on my Model II where it would not fire up Level II BASIC because apparently it had not enough ram, same with another Model II:

32K MEMORY BANK ALLOCATION MAP

0  1  2  3  4  5  6  7  8  9  10  11 12  13  14  15
.  S  .  .  .  .  .  .  .  .  .   .  .   .   .   .

S=OPERATING SYSTEM BANK
.=NO MEMORY BANK PRESENT

INSUFFICIENT MEMORY FOR LEVEL II OPERATION
AT LEAST TWO NON-USER BANKS REQUIRED

...and moving the chips around didn't do much on either. On the 6000, I'm not sure at all what would need to be done to check the memory even though it does share DNA with the older Model II and might have the same memory. I'm assuming on both though it's just using part of the memory for the display and if it was bad memory in the video address space I would at least see a screen of garbled text.

 

[Druid6900]

I believe the 6K is, basically the same as the 12/16(b) setup (it's been a long time and I had a lot of different computers and peripherals to know about when I was running the RS Computer Repair Depot here), so, you'd have 64K of boot memory on the motherboard consisting of a bank of standard 64K x 1 DIP DRAM.