Electronics > Repair
Tek AFG3022B repair
(1/1)
mr ed:
I have a well used afg3022b with a channel 1 error:  2303 : offset error. The service manual is a useless modern no schematic type  and the block diagram is geared for the higher end models.  (That said I did get both outputs working  from the dead state and number 2 is perfectly fine).

Ch 1 works fine up to 40kHz where it seams to roll off down to near zero at 2MHz. The offset actually works fine but has a -50mV offset. That offset is just about at the outside of spec - but cal may be off with the roll off too.

Any ideas on the roll off?  Maybe someone has a better block diagram?
Harry_22:
Two identical channels. One has a problem. You couldn't think of better conditions for troubleshooting.
Compare them step by step.
mr ed:
I know. If it was that easy...but access is very difficult.
mr ed:
Fixed. Key is to get good access. Pull out power supply and tuck it under the CPU board.

Issue was a hidden SMD fuse in parallel with a 0 ohm resistor between relays. Both more or less open but passing DC to 50kHz.when driving a high Z scope.  Not sure why the parallel protection scheme.

As a side note, it's not designed for repair but has an excellent build quality and design with Asian assembly. All Texas Instruments and Burr Brown parts etc.
mr ed:
Correction: the fuse is in parallel with 10k Ohms, that explains the wierd behavior.  Not that the fuse was much use, This is the carnage that was done by someone before I got it.  The good side fuse measures 0.265 Ohm which may be around  3/4 Amp. Where is the bloody schematic Tektronix?
Navigation
Message Index
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod