The beginning

A project log for New life to the Blaupunkt Berlin IQR 83

"The worlds most expensive car radio" "Der Autoradio das Denkt! Und sagt, was es denke!"

anders-dinsenAnders Dinsen 11/28/2023 at 20:120 Comments

I got my Blaupunkt IQR 83 used, not working, and without history: It powered on and could play a tape, but the radio didn't work. My initial idea was to repair it but as I started looking into things, I realized that perhaps there was a better solution than "just" making it work.

But let me go back to why I bought it at all and the nostalgia that got me. 

I grew up north of Copenhagen in a posh area. These radios were outrageously expensive but there were people in my home area who could afford them back then. Mine carries an original sticker from Vedbæk Radio & TV, a shop in a nearby town that used to sell these units. 

In 1983, when the IQR 83 was released, my family drove an old Renault 16. It was a 1973 model as far as I remember, blue where the rust hadn't already eaten the panels. Our car only had a fake radio in the dash but around 1980 my father bought the cheapest Blaupunkt radio he could find and made a wooden box with a pair speakers for it and fitted the assembly under the dash. The sound quality was horrible, but at least he could listen to the news when driving to and from work. 

Much later, when the car was scrapped, I got the old Blaupunkt and took it apart. It eventually went in the trash but thinking about the ealy 1980's Blaupunkt has made me nostalgic about these units.

When I saw the IQR 83 on the used market for a fair price I googled it and found a service manual. Three things caught my attention: The complexity of the system is impressive - it would take time and work to restore it: A good winter project. Also, the firmware for the microcomputer inside is stored in an EPROM meaning it can be disassembled and possibly modified.

But one thing fascinated me even more: The CPU is a Texas Instruments TMS9981, the embedded version of the TMS9900.

My sister used to have a TI-99/4A which had the TMS9900. I spent many hours reading data sheets on CPU's back in the early 1980's, and the TMS9900 series fascinated me. The TI-99/4A was an overcomplicated design for a home computer but the 16-bit CPU had an interesting architecture and a great instruction set. For a while I was looking at the TMS9995 based Cortex as something I could build for myself. I eventually got my hands on a Z80-based motherboard, a pair of diskette drives, and took the CP/M route though.

Getting the chance to finally work with a TMS9900 based system here convinced me. I bought the kit for the asking price from the seller.

Here's what I received nicely packed in the mail: