Can You Put a White Phosphor CRT into an IBM 5155 (Portable Personal PC)?

[jdmcs]

I am having trouble finding technical documentation on the IBM Portable Personal Computer 5155 (which I'm going to simply refer to as the 5155 from here on out) in regards to the voltages that the analog board can output to the CRT. And from seeing Adrian Black try to repair a terminal recently, I learned that some CRTs require different voltages than others. (I, too, had thought that all monochrome CRTs used roughly the same voltage).

I also have a 5155 with a broken CRT on the way to me. It seems like the easiest repair would be to do a tube swap. While I have been unsuccessful at finding an amber CRT (much less a Zenith CRT like IBM used), Macintosh CRTs are readily available. And while it seems anathema to put a Macintosh CRT in a PC, that's better than having no display at all. (Yeah, I know I could plug in an external monitor, but if I'm lugging my 5155 around, I don't want to have to lug a monitor around, too.)

Which leads to my question: can you put a white phosphor CRT into a 5155 and it actually work? Better yet, has anyone done it?

 

[Volvo242GT]

As long as the power requirements are the same, and the signal is compatible, I wouldn't see any reason why not. Remember, Apple did offer the monitor /// in both a greyscale version and the more common green phosphor version.

 

[RetroTheory]

This is my tube swap between a mac and a 5155 monitor chassis , as long as crt band mount is the same you should have no issues

 

[JDW]

@RetroTheory
I certainly don't mean to detract from the main point of this thread, but in regards to your photo, it looks almost like you have that Mac in "dark mode." How did you accomplish that? It's pretty stunning.

And what interface are you using for the naked CRT attached to your Apple //c?

 

[RetroTheory]

@RetroTheory
I certainly don't mean to detract from the main point of this thread, but in regards to your photo, it looks almost like you have that Mac in "dark mode." How did you accomplish that? It's pretty stunning.

And what interface are you using for the naked CRT attached to your Apple //c?

The naked CRT is the CRT module for the IBM 5155 , but all it needs is 12V and an ntsc composite video signal.

The video is inverted with CloseView , with magnification turned off , but leaves a tell-tale zoom box see bottom right , its also a little slow.


There is an invert video program , I have that running on the IIci here running in 1bit , no performance hit.

https://macintoshgarden.org/apps/invert-video

and I wrote a little program to un-invert the corners so they remain black

InvertCorners_VintageMacintosh/invertedcorners.jpg at main · retrotheory/InvertCorners_VintageMacintosh

Utility for removing or restoring the rounded corners on vintage Macintosh desktop - retrotheory/InvertCorners_VintageMacintosh

github.com

The SE30 is currently running an SE board and invert video program wouldn't work, so I used CloseView. I think invert video program will run on a real SE30 just have not tried it yet. The IIci is using a color monitor running in B&W 1bit, but externally RGB are mixed to give amber effect.



Special treat

https://tinkerdifferent.com/members/retrotheory.45/#profile-post-67

 

[joevt]

So the IBM 5155 has an amber CRT for displaying NTSC but it works for non-NTSC in a SE or SE30 and the SE30's CRT can do NTSC using the 5155 CRT module (which is the circuit that controls the CRT and not the CRT itself).

That means there's no real difference between a CRT for composite and non-composite video?

Regarding the InvertVideo app, why wouldn't it work with emulators? Doesn't it just change the color palette?