I am getting faster with every unit. There are some neuralgic points that always fail. On the power supply it is definitely the transistor 7477 which was in almost all units broken or got killed during ling time testing. On the amplifier part one TDA2030 was not working – only a buzzing noise on its output. To check it I […]
Category: Amplifier
Video about AM/FM and amplifier panel added
Well, here is another episode this time with the am/fm and amplifier panel. Since this panel is working fine there is not much to do. I explain what failed on other units and put thermal paste onto the heatsinks. This helps a lot to cool the amplifiers down. https://youtu.be/_CosOQB9Aho
Last problems for unit 2 solved
The last days I was working on the final source code for the tape deck CPU whilst I noticed another problem – it was not possible to read the states of the write protection of side A & B and the event when the CD ends was not fired. It took a while and I had to dismantle the machine […]
Repairing the amplifier – Part2
Well, the preamplifier is working and not to continue with the TDA2030. Since the channels are separated but both do not have a signal it was quite clear it can only be a control of both channels which is not working. Luckily there is only one circuit that can cause the troubles. The circuit around 7310-7314 mutes the signal for […]
Repairing the amplifier – Part 1
After I have repaired the power supply of the second unit and check all of the provided voltages it was time to continue with the amplifier. Since there is no sound on both channels it must have something to do with either the supply or controls. In a first step I checked the voltages and noticed F with +38V was […]