Model 1 possible power supply/keyboard issue

[pharaoh46]

Hi all,
I've got a TRS-80 Model 1 48K w/EI and floppy drive hooked up to a DMP through a printer switch (I share the printer w/a Model 4).

Anyway, when I power up, the standard character gibberish displays, but the characters themselves are distorted (for example, the letters don't look like letters, same w/numbers, etc.). I press the reset button and Break repeatedly, but the Memory Size? prompt doesn't display. I've tried cleaning all the contacts and plugs on the keyboard, expansion interface, and drive. No success. I also looked at the plug connecting the keyboard's power supply to the keyboard, and the cable going into the plug appears frayed & loose. Could this be the issue, or is it something else? Appreciate any input/guidance. Thanks in advance.
--John

[Bob Campbell]

On 6/2/21 12:16 PM, pharaoh46 wrote:

> Anyway, when I power up, the standard character gibberish displays, but the characters themselves are distorted (for example, the letters don't look like letters, same w/numbers, etc.). I press the reset button and Break repeatedly, but the Memory Size? prompt doesn't display. I've tried cleaning all the contacts and plugs on the keyboard, expansion interface, and drive. No success. I also looked at the plug connecting the keyboard's power supply to the keyboard, and the cable going into the plug appears frayed & loose. Could this be the issue, or is it something else? Appreciate any input/guidance. Thanks in advance.

With a 43 year old POS like the TRS-80 Model 1 is/was, it could be
literally anything.

I would disconnect everything and then power up the KB alone. Since
you have the EI, it has the same power supply as the KB. Swap those and
see if that fixes it.

[pharaoh46]

Yeah, I was thinking the power supply since it even after I press the reset button, nothing happens. I'll try that and see what happens. If it's a power supply, I'll order a new one on eBay or something. Thanks.

[Bill Gunshannon]

Unless you are obsessed with visual purity you can easily replace the
power supply with something more reliable. According to the Technical
Reference Manual it runs on +5/+12/-5 volts. Pretty standard and easy
to cobble together if you didn't want to buy one.

bill

[Bill Gunshannon]

On 6/12/21 1:35 AM, pharaoh46 wrote:

Being someone who actually still has Model 1's that they use,
this brings up an interesting question. How common is power
supply failure? Being as both the base unit and the E/I run
off of the same class of power supply would it make sense
replace them with something like a PC Class power supply?
And whilw we are at it, if you were using something better,
could the base unit and E/I be run from the same power supply?

bill

[pharaoh46]

Thanks everyone for your input. I just tried the E/I power supply w/the keyboard. Nothing. Still the same gibberish on screen, and when I press Reset and Break repeatedly, still nothing happens. At this point I'm guessing the keyboard is hosed.