VT100 to VT103 conversion

[hush]

hey all! i recently picked up a spare VT103 backplane on ebay thinking since they (VT103s) are quite rare, it might be possible to retrofit it into my VT100- as far as i know they are the exact same physical dimensions and all, just the power supply is beefier and there is an LSI11 backplane. that being said, i am not sure if there are any pitfalls that i should be aware of. apart from the stronger power supply (which can be provided via ATX conversion until i can find a genuine model), is there anything that i should be aware of? has anyone tried this before?

thank you!

 

[Schroeder]

Not sure if VT103 are really rare, maybe they are kind of customized like mine which was used at a aircraft maintenance factory. It has an additional serial breakout box. I can take some photos when I'm back home.

 

[hush]

anything you can provide would be very useful, thank you!

 

[jasperwilde09]

Hey, so if you're thinking about swapping out the backplane of your VT100 with one from a VT103, you might want to think twice. Here's why:
1. Electrical Stuff: personality test
So, besides the obvious difference in the power supply, there could be other electrical variations between the two backplanes. If the voltages or current requirements don't match up, you could end up frying some of your VT100 components. Not cool.
2. Functionality:
The backplane in the VT103 is designed for specific functions that your VT100 might not have. So, trying to make it work could lead to all sorts of weird behavior or just straight-up malfunctions. It's like trying to fit a square peg into a round hole – it's just not gonna work smoothly.

 

[saipan59]

Hey, so if you're thinking about swapping out the backplane of your VT100 with one from a VT103, you might want to think twice. Here's why:
1. Electrical Stuff: personality test
So, besides the obvious difference in the power supply, there could be other electrical variations between the two backplanes. If the voltages or current requirements don't match up, you could end up frying some of your VT100 components. Not cool.
2. Functionality:
The backplane in the VT103 is designed for specific functions that your VT100 might not have. So, trying to make it work could lead to all sorts of weird behavior or just straight-up malfunctions. It's like trying to fit a square peg into a round hole – it's just not gonna work smoothly.

I had a VT103 that I bought in the 80's via the 'Employee Purchase Program'. It cost me over $4K. I still have the Q-bus backplane from it, but nothing else. It has an edge connector for the VT100 board to plug into.

Check the 103 print set to be sure, but I think the VT100 module (that does the terminal functionality) is the same in a 100 or 103. The difference would be in the cabling for the serial ports - the VT100 board would go to one of the LSI serial ports, instead of to the rear bulkhead. A second LSI port goes to the bulkhead as a printer port.
So, the change from 100 to 103 is really just a bigger PS, and a physical space for the bigger BP (which happens to include 4x4 Q-bus slots).

Also, some versions had a dual TU58 drive as well - that requires a different plastic case that is unique to the 103. But you don't have to do the TU58.

Pete