Heineken
23-04-2021, 07:25 PM
Since one of the three amplifiers (http://www.nsxcb.co.uk/showthread.php?15905-Speaker-Amplifer-Repair-and-Capacitor-Replacement) received couldn't be repaired, the owner bought a replacement unit from an Australian seller. The state was described as "working" - which was technically correct but only for about ten minutes and with reduced volume. From a first picture it could be seen that it's one of the early boards equipped with green capacitors.
14242
14243
Interestingly, the large voltage stabilizing capacitors were still OK but all the green ones had leaked. The area was carefully cleaned, including the removal of contaminated silk screen, solder added for further protection and new capacitors installed. Luckily the capacitors from the impossible-to-be-repaired amplifier were matching and could be simply taken over.
14244
14245
A 30 minutes test run at increased volume was completed without any issues and at the correct voltage. After applying new conformal coating and hot glue to secure the coils it's now considered repaired and will be on the way to its owner soon. Good to know that his audio system should now be completed and went from completely dead to fully working (even though it took a few months).
14242
14243
Interestingly, the large voltage stabilizing capacitors were still OK but all the green ones had leaked. The area was carefully cleaned, including the removal of contaminated silk screen, solder added for further protection and new capacitors installed. Luckily the capacitors from the impossible-to-be-repaired amplifier were matching and could be simply taken over.
14244
14245
A 30 minutes test run at increased volume was completed without any issues and at the correct voltage. After applying new conformal coating and hot glue to secure the coils it's now considered repaired and will be on the way to its owner soon. Good to know that his audio system should now be completed and went from completely dead to fully working (even though it took a few months).