Please see the attached photo.
After considerable searching, and chasing false leads, I believe that the 100 ohm
trimmer pot on the left is the correct video pot for an NTI Apple-1 board.
I hope it is, as I had to purchase 20 !!.
(The most irritating false lead was an ebay seller, incorrectly claiming that
his Helitrim 100 ohm pots were correct for an Apple-1)
The photos of an apple-1 NTI board that I have are not that clear.
Can anyone confirm that the pot on the left is the correct pot please?
This question is something I had to face (since I am building a NTI replica). The potmeter I have ordered is a spectrol 75H501 since I could not find the correct one (75H101). The 501 is a 500Ohm version instead of the normal 100Ohm. You sometimes find the 75RH101 specified as 75H101. The correct one does not seem have a black round base, only white with a metal cap:
This is what I have been able to see from the NTI pictures online. If someone has different information on this, please inform.
I have several Helitrim 100 ohm round pots with the black trim stem. They look identical to what is in one picture of an original Apple I. I also have a purple ceramic with gold top house numbered 6820 from Motorola that came to me in an AIM-65 display module that normally used the 6520. It worked just fine in that application. I have several Intel 3621 PROMs that are 256x4 T/S and some 3622 512x4 T/S that I'm trying to get programmed to the Apple I code. If anyone has any interest in any of these, please send me a PM.
Can you post a pic of the Helitrim pot? Looking at pictures of my original NTI board the pot is all white I don’t see any black. I actually checked all my pictures of various NTI boards also. I was planning a visit to my board this weekend at the bank, I will triple check this in person.
This is the trim pot I have several of in both tinned and gold plated leads 100 ohm.
Well, I cut out the potentiometer part from several NTI Apple pictures in the registry (London Science museum, Bern, Dinxdof, Living computers +), and they all show a potentiometer with a white base and white screw. It has a metal ring around the top with a metal notch like the 75H101:
I haven't been able to find any original NTI boards with the Helix potentiometer (but they do look nice). Which Apple 1 did you seen it on?