Hi,
I'm new to this site, and am looking for advice about this generator. I just bought one on ebay, and I know, you get what you expect from there. Anyway, it works, but seems to not attenuate below -30 dbm. When I try to go past that level, the output disappears. This applies for both RF and sweep outputs. I looked in the manual, and it looks like there are 5 dbm electro-mechanical steps in the attenuator, with electronic attenuation between steps. These are related to card A12A1from what I can tell. This is my question; Does anyone know about these, and where do the AT1, and AT2 attenuator networks reside? Also, are these basically resistor bridges that are additive, and if so, can I repair one if it's got an open resistor?
Thanks,
Bruce
I'm new to this site, and am looking for advice about this generator. I just bought one on ebay, and I know, you get what you expect from there. Anyway, it works, but seems to not attenuate below -30 dbm. When I try to go past that level, the output disappears. This applies for both RF and sweep outputs. I looked in the manual, and it looks like there are 5 dbm electro-mechanical steps in the attenuator, with electronic attenuation between steps. These are related to card A12A1from what I can tell. This is my question; Does anyone know about these, and where do the AT1, and AT2 attenuator networks reside? Also, are these basically resistor bridges that are additive, and if so, can I repair one if it's got an open resistor?
Thanks,
Bruce
These attenautors should be "card" attenuators, where the contacts, normally connect to a thru line. When attenuation is turned on, the contacts will touch a thinfilm attenuator card. There are usually three or four cards in the attenuator with different attenuation levels. For example, a 5, 10, and 20dB cardset can give you 0-35 dB attenution in 5 dB steps. One or more of these cards are probably either broken or dirty.
If I'm not mistaken, the 8663A probably uses the following parts for the attenuators: 33321-60027 and 33321-60028. These parts are available at http://www.agilent.com/find/parts.
As for self repair, if you're careful, you can probably take these apart and clean and/or burnish the contacts and attenuator cards. Otherwise, you can always remove them and use external attenuation instead.