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I have recently finished a Test Card generator construction project. This one is a little unusual in that it can generate simultaneously 12 different Test pattern of different standards. For example it does NSTC, PAL, The old UK 405 line etc. Very helpful for repairing and adjusting vintage...

I just noticed this on ebay, these do not appear very often: https://www.ebay.com/itm/186375533453? They are a very special capacitance keyboard. The ASCII data on the output stays stable after a key press. They also do very well if the pads in them are replaced by those from a SUN-4 Keyboard...

There are some RTC clock modules such as the BQ4830Y which, with an adapter board, can plug into a spare ROM socket on the PET. These look like RAM to the computer. But, I was wondering, does anybody know if there is an RTC module (perhaps a Dallas part) that would plug directly into a spare...

When plastic ages it hardens, and if it is in an application of some force transfer, it can fracture. I'm posting a plastic repair job here on a small sized item, not because it is part of a computer or disk drive , but to draw attention to three very helpful tools/parts to have in the workshop...

I have a perfectly working SFD-1001, that is to the extent that it formats and writes disks fine and there are no issues reading what it has written. When I got the unit though I was suspicious that somebody had been working on the 5.25 drive unit in the past, because of tooling marks on some...

One thing that really bothers me is when some piece of apparatus has a line power cord dangling out of it. Both my AIM-65 and my PET has this. The cord is always dangling down and trailing behind like the Tail on an Alien moving them around. I much prefer standard IEC panel line power...

Is there a readily available EEprom (electrically erasable ROM) that is pin pin compatible with either the 2532 or the 2732. Ideally there would be a different type that could directly replace each, and also be readily programmable in common programmers like the GQ-4x. I have not been able to...

I have been building more Votrax Type 'N Talk units. I had enough vintage IC's and ROM's to make 5 units in total. The thing I like about these is that they are basically an SBC, with 1k of SRAM, a ROM & CPU. They contain all of the sub-systems to safely support and operate the SC-01A speech...

About 4 years ago I noticed that the pcb mounted 3.5mm audio jack sockets used for the tape connections on the SOL-20 mobo, were a fairly unique and rare part. They happened to be the same ones used in the Votrax TNT for the speaker. They have a very specific geometry and pin spacing where they...

Normally, I'm good at spotting fakes, that is if the seller actually sends me what is in the photo. A while back I was on the hunt for some 2732 UV eproms. I found some good looking ones (in the photos at least) from a seller in China. They had large sized dies and the part appeared to be the...

The more I played around with the AIM-65, the more I realized (like in my SOL-20) it would be good to have extra ROM space. For example to hold small programs such as one to initialize the RM-65 video card, and or the AH5050 disk filer. Possibly there might be some space hiding in the existing...

A while back I had a lot of success replicating the RM-65 video card. It has an adapter card made by Rockwell, to make it plug onto the AIM-65. One reason it worked so well is that it contains firmware designed by Rockwell , specifically for use with the AIM-65. ( I struggle more with third...

I had never used my AIM-65 with tape storage, so I thought I would have a go connecting to a Tape Deck. All did not go as smoothly as planned. Firstly I didn't like the idea shown in the manual on connecting the lead wires to an Edge connector. I figured it would be a lot better to combine the...

I'm struggling with the AIM-65 user manual copies. All the links online I can find appear to be exactly the same poor copy of the manual that has circulated the internet. Even the one I was supplied with on a disk that came with my machine was the same poor copy. The copy has created problems...

The power adapter for the Votrax unit has the approximate specifications: (from what I have gathered from photographs) was rated a 17VAC rms CT @ 1A and 20V DC @ 0.5A. The 20V "DC" came about from two diodes that where contained in it ( no filter caps in it), from a 30V CT winding (15V aside)...

Processor Technology realized that the punters were struggling to assemble their complex memory card kits in 1978 , they must have had a lot of returns with solder bridges and heat damaged parts etc. So they offered their 16kRA dynamic memory card, assembled by them as a "Semikit". See...

I have been doing some work lately making a non-volatile memory board for my PET. It plugs onto the Dynamic PET's board J4 & J9 and has two additional wires which connect it to the pcb. One is for the 5V power, the other to inhibit DRAM reads. The non-volatile memory then is the one in use. I...

I thought I would start a new thread on this and a summary of what transpires. This has been built to help solve a problem that has been bothering me since the 1980's, how to replicate this IC for one of my vintage Conrac VDU's. The original ROM file is not available. I want to extract the...

Recently there was talk on a thread about the advantages of digital scopes, especially for slow events, because of the memory. I bought up the topic of storage scopes, like the ones Tek made and early types that simply had long persistence phosphors. I powered up my vintage Telequipment D52...

I saw this on ebay: https://www.ebay.com/itm/275656911119? When I bought my SOL a few years back it was less than $1000. However the price of these sorts of things has been increasing lately (just look at the KIM-1), let alone the Apple-1. Probably, at this stage of the "game" this price is...