Broken ZX-24 and Zx-24a

[G Herzog]

Hi,
I am sorting through some old items. I have two that appear defective.

One is a ZX-24 that will not recognize ATN, though seems to be operating as the Red/Grn leds blink. I have even managed an Emergency firmware upload to 3.0.3. in IDE. But it still won't load new programs.

The other is a ZX-24a that was being fed 13.5volts that shorted yesterday. The 78l05 appears burned out, but using regulated +5, it too seems to be functioning somewhat. But it won't recognize ATN and won't reprogram. either. It has already received upgraded firmware and won't take a reload of it by normal or emergency means in IDE

As I am in Taiwan, I am wondering if it is worthwhile to seek repair of either. I do have other ZX-24a that are unused with the latest firmware installed. So I guess this is one last appeal before they head to the trash can.

I've yet to run ZLOAD tests, but that is about all. The COM port is correct and the cable is fine as I have been working the same configuration with the good ZX-24as.

[dkinzer]

I have even managed an Emergency firmware upload to 3.0.3. in IDE. But it still won't load new programs.

Being able to update in emergency mode confirms that the serial I/O is working properly. If it won't download a program the issue is likely in the ATN circuitry.

It has already received upgraded firmware and won't take a reload of it by normal or emergency means in IDE.

This sounds like the inverter used in the serial I/O is defective in addition to the regulator.

As I am in Taiwan, I am wondering if it is worthwhile to seek repair of either.

The one with the bad regulator is likely to be more difficult to repair. We would be happy to spend a little time on them to see what can be done. We have one remaining ZX-24 on hand that we would send you if we cannot repair yours. The stock of ZX-24a is dwindling but we still have some and we would replace the ZX-24a if we cannot repair it.

Sending the two back by regular mail is probably the best option as it is the least expensive. We would send them back the same way (USPS First Class International) unless you wanted to pay extra for Priority Mail or another shipping option.

The address to send them to is:
Elba Corp.
10915 SW Avocet Ct.
Beaverton, OR 97007

[G Herzog]

Thanks for your quick response. I was really hoping there was something rather simple that I'd overlooked. But I do admit that these were the first units I had and subject to the considerable abuses of a beginner.

Oddly the ZX-24a now works with voltage regulator as well. So both seem to be mainly suffering from serial port problems at this point. I guess I will try one last round of testing with ZLOAD to determine the ATN circuitry and then decide what to do. (I'll advise you if I do decide to mail them in.) I still have four new unused ZX-24a units on hand.

Seeing as the units are out of production, I am leaning toward cutting my losses - though I appreciate your willingness to service the units. Rebuilds are never quite as reliable as brand new and shipping to and from Taiwan is rather expensive.

I suspect that a couple of kids here in Taiwan would enjoy having their own 'personal computer' to show friends. The fact that they do nothing but perpetually blink red and green might be rather unimportant to them.

Alternatively, I might see if I can replace the SMDs on my own. That certainly would be a new challenge to me.

I am more attracted to buy your newer faster products. The ZX-24 doesn't seem to support all the features that have evolved in the software. What I really love about the ZXes are the built in RTO and having 8 ADC pins. Other 'Stamp format' chips require these things to be tacked on. Also, your documentation is excellent.

The fact that you are willing to consider swapping if beyond repair is quite generous.