Bridgeport Series 1 CNC

[seemackParticipant @seemack]

Yes you can run from RAM but you need to transfer it there first by putting in the code 961025. This puts you into the Markers and plc but you need a screen to go down that path.

Unlikely you have bad epproms but only way without screen is to take them out and read them.

[tomcncParticipant @tomcnc]

 

If I were to take out the eproms and read them, how would I know they were bad. I don’t have the original stuff that was programmed into them.

 

I have been going around the board with the TMS 9937 chip (a display driver). The board also contains a TMS 9995 (a

microprocessor).

The DS pin  (data strobe off the top of my head) has a signal on it but the CS (chip select  has not).

I will probe further. It’s a bit like looking for a needle in a haystack, in the dark, and not knowing what a needle looks like (for me anyways).

I have wheeled out my logic probe. It’s been a while. It is homemade. It has three lights. One lights if the pin is +5.

Another lights if the pin is 0V and the last light lights if there is a pulse on the pin.

 

Can you substitute a TNC 155B for a TNC 150B do you know. There is one on ebay at not too outrageous of a price.

https://www.ebay.co.uk/itm/327265911229 (about £350)

 

Might be better to start spending money on a more modern refit.

 

Thanks,

Tom

[seemackParticipant @seemack]

Hi Tom

It’s not giving you much joy yet, is it.

I have the same machine as you,  and it originally had a 151B on it. I have updated to the 155B due to screen issues and all connections are the same except the screen connections, which is a DB9. I would download the service manuals for both and compare both. My guess is it will be a straight swap as yours is a B model also.

That 155B looks in good condition, so it’s quite a good option to get your machine going without a lot of changes. And at that price it still makes your machine a good buy provided it is a working unit.

Not that your screen will not work on the 155B as it has a different Hsync and Vsync, but I have already posted earlier how to get a modern HDMI screen working.

[seemackParticipant @seemack]

A final check which I may have already said is the LEDs will all come on initially and stay on while it’s going through it’s check. Without the screen it’s hard to know what’s happening but if everything except the screen is OK then waiting at least 20 seconds then press the CE button at least twice (more doesn’t matter incase there are other messages on the screen you cannot see) then all LEDs should go off as you are at the MP entering prompt and your controlis good. If the LEDs stay on then you have and startup error on the screen which you cannot see.

[seemackParticipant @seemack]

How did you go @tomcnc?

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