Pete,
I've got a several of tips for you to add to the list.
1. For the Flex Cables (FDC & Serial Board): How do I easily Insert/Remove the Flex cables?
Wrap the Flex Cables around a wooden pencil 180 degrees when Inserting/Removing them.
2. Where do I get a replacement Door Latch Hinge for my Tandon TM-100?
Print one with a 3D Printer from the files that are on thingiverse. (This project will/should be finished
in the next few weeks.)
3. How do I update the TRS-80 Model 1 Level 2 to ROM Version 1.3 from Version 1.1?
REF: trs8bit0801.pdf page 13
4. Lowercase Mod for Model 1 Information:
http://www.vcfed.org/forum/showthre...l-1-in-2016/page2&highlight=Model+1+Lowercase
I simplified it this way which has served me well since the 80s.
If your character generator (Z29) last 4 numbers are 3001 or 6670, then you do the mod Lowercase with Upper from Custom TRS-80
If your character generator last for numbers are 6673 or 6674, then you do the Radio Shack lowercase mod, from the same book.
All other LC mods are complicated or unnecessary in this day and age, and in fact when I buy systems with other mods I undo
them and set them up as listed, above.
For the record:
3001 : early systems, lowercase but no descenders, and a flying 'a' due to Motorola manufacturing fault (so they sold these
chips cheap to RS who figured they didn't need LC anyway)
6670 : mid-production systems, same as above but with no flying 'a'
6673 : late systems, custom part made especially for the M1 for Radio Shack and included with most late 79 and 1980 machines.
By this time RS was selling the LC modification "kit" for $99 but if the computer already had the 6673 then the 1-min job
was to cut the trace, install the stacked 2102s into the already fitted socket, and solder two wires. It probably took
longer for the soldering iron to warm up than to make the mod.
Ian.
5. Composite Cable for Model 1
REF: trs8bit0802.pdf page 15
Composite cable for TRS-80 Model 1.
Signal - RED - Pin 4 of Din Plug
Shield - wire - Pin 5 of Din Plug
Radio Shack. Catalog number 278-255 Adapter works good.
Also
https://groups.yahoo.com/neo/groups/TRS-80/conversations/messages/9588
The Model 1 video output is a standard composite, but it does have a
DC bias voltage on it. You can make a cable and connect the M1 video
output to any composite video monitor that has a DC blocking capacitor
on the input. I used an old black and white Sony security camera
monitor for many decades, no problem.
6. TRS-80 ROM Versions Info
Model 1 ROMS
Level 1
Z1 ROMA 4K x 8 450ns 0x0000 0x0FFF ROM1A1
Level II
Z1 ROMA 4K x 8 450ns 0x0000 0x0FFF ROM1A2
Z2 ROMB 4K x 8 450ns 0x1000 0x1FFF ROM1B2
Z3 ROMC 4K x 8 450ns 0x2000 0x2FFF ROM1C2
Model 3 ROMS
Level 1
U104 ROMA 4K x 8 450ns 0x0000 0x0FFF ROM3A1
Level 2
U104 ROMA 8K x 8 450ns 0x0000 0x1FFF ROM3A2
U105 ROMB 4K x 8 450ns 0x2000 0x2FFF ROM3B2
U106 ROMC 2K x 8 450ns 0x3000 0x3FFF - less 2 bytes - 37E8 & 37E9 ROM3C2
Model 4 ROMS
Level 1
U68 ROMA 4K x 8 450ns 0x0000 0x0FFF ROM4A1
Level 2
U68 ROMA 8K x 8 450ns 0x0000 0x1FFF ROM4A2
U69 ROMB 4K x 8 450ns 0x2000 0x2FFF ROM4B2
U70 ROMC 2K x 8 450ns 0x3000 0x37FF - less 2 bytes - 37E8 & 37E9 ROM4C2
7. Testing the Z80 Address Lines
REF: trs8bit0802.pdf page 60
Thanks
Larry
