We received a 129 keypunch machine from Darien, CT. We discovered that there are several problems with this unit. Unfortunately it uses SLT cards with SLD modules. Our scope shows us that at least one module on one card is not working correctly. However, we don't have logic diagrams for these cards and the modules consist of several transistors and diodes so the problem will be hard to locate and fix. (SMS cards are single layer PC boards with discrete components, SLT cards are multi-layer with complex components and very hard to obtain).