Mike Williams - Husqvarna Prisma

What are they?

The Prisma is the successor to the 2000 series which are sub-modelled 6nnn (where n is a digit between 0 to 9) and referred to as 6000 series in the USA. Model numbers include 940, 945, 950, 960, 970, 980 and 990. The higher the model number, the more features it has.
In the USA Husqvarnas were called Viking, of course, but Prisma was also deleted from the model name and they are referred to in the USA as 7000 series. They were made immediately after the 6690 ceased production in the early 80s and were made until the end of the 1980s

What are the problems?

As you would expect, plastic is a big issue with these machines: They rarely keep their hinged bobbin cover because the hinges usually snap off, either on the movable part or the caddy.
The power supply capacitor (0.1uF) is a Rifa and often explodes or melts down without warning. Sometimes it takes out one or more of the diodes and occasionally a piece of the circuit board.
There are many electronic components in the front control boards that can fail. Almost all of these are replaceable.

It sounds like the Prisma is a bit of a lost cause but they are not. They are lovely to use, very fast, full of features, and quite reliable. Being computerised, they can do a lot more than most previous mechanical models, but they lack the low gear of the 2000 series.

I have been able to fix almost everything on these machines. The one that got away was a 945 that blew out part of its power supply board. It could be fixed by soldering bridging wires but with an actual hole in the PCB I felt it was a good place to draw a line. In the coming months I will add details on how to diagnose and repair problems with these machines. My Norwegian friend Theodor has assisted me in diagnosing problems with Prismas and is also committed to repairing these machines, so if you need a repair kit Syrep.no might have one. You can also donate to his gofundme so he can continue the good work.