The ASR-10 SCSI and digital option boards are becoming very difficult to find. I thought I’d take on the task of reverse engineering them and creating new ones. The SP-3 and the DI-10 are both completed now and are for sale.
The DI-10 has issues when installed in a rack ASR-10. What happens is the digital output, over time, will become noisier and noisier, and will eventually be nothing but white noise. I’ve determined that it is an overheating problem but haven’t found what part(s) exactly are at fault. Looking at the signals on the ‘scope, I can see that the relationship between the serial clock, serial data, and sample clock change over time. I suspect that this problem may be a factor in the low sales of the DI-10. It may be possible to solve the problem by either putting a stick-on heatsink onto the overheating part, or installing a cooling fan. Or, leaving the lid off the ASR rack.