I have an AW07A analyzer that I have an issue with. (this is a bit of an older unit, it has the 8AA battery pack, and no 220Mhz on the VHF band, though UHF goes down to about 225Mhz.) RF board has a date code 07/27/12)
SWR and frequency readings work fine, however I have no impedance readings. Verified by looking at a signal source from my function generator, and looking at the SWR of my 10m vertical.
The odd time it will flash some gibberish quickly, but 99% of the time the display just reads Z>1K
If I switch to LC mode and attach at 151 cap (150pF) via the N-BNC adaptor and my BNC clip lead cable It flashes between >1.5k and random readings of between 4 - 8 pF
I am not sure if this is being caused by a bad diode or maybe a broken or loose connection.
I have opened it up and completely dissasembled the untit and looked over it carefully for bad solder joints, I found a couple shady looking one that I touched up, but did not help.
Where should I be looking for a solution, the RF board or the main Board? Is the LC measurement circuit on the main board? I cannot find a schematic for these units so It is hard to tell what is what. There is a bank of transistors at the bottom of the main board supplimented with some reisstors, capacitors and inductors, they look to be tuned circuits, could this be the LC measurement section for each band?
Thank you.
SWR and frequency readings work fine, however I have no impedance readings. Verified by looking at a signal source from my function generator, and looking at the SWR of my 10m vertical.
The odd time it will flash some gibberish quickly, but 99% of the time the display just reads Z>1K
If I switch to LC mode and attach at 151 cap (150pF) via the N-BNC adaptor and my BNC clip lead cable It flashes between >1.5k and random readings of between 4 - 8 pF
I am not sure if this is being caused by a bad diode or maybe a broken or loose connection.
I have opened it up and completely dissasembled the untit and looked over it carefully for bad solder joints, I found a couple shady looking one that I touched up, but did not help.
Where should I be looking for a solution, the RF board or the main Board? Is the LC measurement circuit on the main board? I cannot find a schematic for these units so It is hard to tell what is what. There is a bank of transistors at the bottom of the main board supplimented with some reisstors, capacitors and inductors, they look to be tuned circuits, could this be the LC measurement section for each band?
Thank you.
MFJ-266 / AW07A : No impedance reading.
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