About my H8
Dave Runkle
HI all,
Thank you to all those who answer my first post here. The information is indeed helpful.
Glen had asked a few questions which I will answer here in a separate post.
Q: Perhaps you can tell us more about your system – what options does it have and what are your plans?
The H8 I received came with the basic H8 system, two H8-3 static memory cards with 8K on each, a HW-16 static memory card with 16K and a H8-5 cassette and serial interface card. The system with all cards are fully operational. I performed a 48 hours power-on memory test with zero errors.
My short term plan is to finish the restore, find a set of extra replacement parts, collect software and re-learn forgotten lessons learned.
Back in the late 70s, many people added a cooling fan to their H8s. Many of the units I see running today also have added cooling fans. It tuned out that the H8 I received also had an added fan. But the fan that came with the unit was an over sized, 120VAC unit, crudely wired into the mains AC power section. The wire used looks like some type of 18AWG twin lead extension cord zip cable. Both of the solder joints on the AC cord where cool joints and had been arcing for some time. The fan I'll be using will be a much quieter, 12VDC, brush-less type that will use the holes already in the case from the previous fan install.
Q: How are you working with the tape version? Are you using actual tapes from the 70’s with a cassette machine? How’s that working after all these years? Is it reliable?
I am not using old vintage tapes from the 70s.
I have added a serial signal interface circuit based on the MAX232A chip to the cassette tape's serial USART TxD and RxD lines on the H8-5 card. I installed the resulting serial interface daughter board using an existing hold in the board. It is wired it to the card in a method that required me to not cut any foil on the board. So I can restore the H8-5 board when I need to. This added circuit allowed me to connect the cassette's USART ship to my lab's laptop computer via RS232 signal levels. It is via this I send/receive H8T files I downloaded from the SEBHC site. This is how I'm loading the BH BASIC by the way. While I did find the software utilities to handle these transfers, I'm using my old standby, RealTerm to send/receive the H8T files for now.
I'm hoping to create a solution that will give me a switch to place the H8-5 card in either normal Tape interface mode or PC-to-H8 serial mode. BTW, once I perfect this update, I'll let you all know what I did. For that matter if any of you have a good idea I would be interested to learn about it.
I know that at some point I'll start down the H17 or like trail. I have already started reading about what other have been doing. My preference would be to have the original Heathkit solution. But finding a restore-able H17 may be a little difficult now...but then this is the group that already knows this. Right now I'm trying to decide if I should place my name on the list for one of those cool looks hard sector punches.
Q: Any war stories to share?
I'll answer this by pointing you to my humble web site at www.astrorat.com. This is where I share many of my past war stories. I see from my web counter some of you may have already had a look. The site is simple and is just my personal soup-box to showing off what projects I'm working on in my spare time.
Dave
Glenn Roberts
Dave: thanks for sharing all this. Perhaps some day you can share more details on the daughterboard in case someone wants to replicate this. Very nice way to solve the problem.
Loved looking at the pictures on your site. You’ve got some great stuff there! Very cool to see the VCFMW pix too!
- Glenn
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