FAIL 01/90
We must point out that we do not claim this will work every time especially if you are trying to alter an MLM for extra features.
While reprogramming a Spectra, power accidently got killed to the radio. You know what happened next... FAIL 01/90.
The next day, we decided to do some programming on a VHF Syntor X9000. Well everything was on the bench, including the Spectra that got toasted. Not paying attention to what we were doing, everything was hooked up, and when we turned on the 9000 control head, some weird fail codes appeared.
After tracing the cable from the head, we realized it was connected to the Spectra. We had accidently put the Syntor X9000 head on the Spectra. More importantly, we noticed that the radio was no longer the the dreaded FAIL 01/90. Being curious, we put the A7 head back on the Spectra, and sure enough got the FAIL 01/90 cycle.
We put the 9000 head back on and went through the standard procedures like re-entering the serial number and reprogramming the radio. Well it worked. The radio came back to life.
This was tried on a couple different radios (scrambling them and recovering them). Each time when putting the Syntor X9000 head on the radio, it would cause the radio to stay on so that we could refresh the MLM back to its original state.
Again, we do not recommend this practice for modifying an MLM, only to as a last resort to try and restore it.
There are some other things to check if you are getting a FAIL 01/90. These are listed below:
If you are using it as the second head, change it to the primary and see if it still fails. If it works, you need a new dual interconnect port for your remotes.
If that is not the problem, then check all the pins on the head. Make sure all of them are getting continuity on the board and through the cable. I have had some that had bad pins and I ended up flowing some solder on them to get them to make better contact when the cable was hooked up.
You might also check the solder connections on the control head board, and trace them through out the head. You might have a failed SMD somewhere that is keeping a signal from getting through. I recently picked up a 1066 that would not key up. I ended up putting a jumper across the PTT pin at the mic connector to the PTT line on the cable connector. I found that alot of the A9 heads start to go bad at the pin connectors and the layered boards because to much flexing and pressure applied when constantly removing or cheap installation.
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Here's some information from Batlabs .........and more listed in the following post!