Hi everybody. My restoration of two GF-8989s is going very well. Lots of progress. Trying to nail all of the technical issues before getting too deep in to the cosmetic. One thing that is sort of frustrating is that as a retired electronic engineer - the GF-8989 is defo not designed for test ! The RF board has TPs fitted and is easily accessible. The main board is very different !!! The SM documents several TPs - but none are actually on the PCB :-( To make matters worse the location of the monitoring points to set various levels for PB/REC sensitivity are only accessible on the back of the main PCB. However, you cannot access the back of the PCB when the unit is all mounted to the back of the case - grrrrrr. So, I am wondering whether in the factory they used a test rig to set everything up and then installed things in the case ??? I am thinking I am going to have to rig something up made of batten wood to allow me to physically mate the PCBs and cassette mechanism so I can do these adjustments. Or am I missing something very obvious ? Appreciate any insights and if I do come up with something I will happily share details. Oh and one more thing. One unit had a tape head that was pretty much destroyed - virtually no playback level (even though ebay seller claimed fully functional). Tape head is officially a HF0096 - absolutely no joy finding that. However, I did find a guy selling brand new HF0098. So for £12 I thought why not have a punt. Fitted it and it works like a charm ! Getting specs on these things is virtually impossible - mechanically it looks like an exact match. So then it's just the electrical - maybe a different inductance ? I'm going to let my ears decide if this is usable. Seller did claim it is METAL compatible so okay on that front. Next step is to fix azimuth and see how it sounds. Again, I will follow-up in due course with any findings. If anyone has any technical info on these heads I'd really appreciate it.
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