Agilent d4400 output board replacement - Page 1
Forum section: electronics / repair

author: kjk24
author_rank: Regular Contributor
timestamp: December 16, 2017, 11:29:41 am
content: Hi,i have a Agilent e4433a from the bay without the output board insight (nice present if I opened it up).And Other Fails:1. display not working2. attenuator properly defekt (wars not connected and someone try to fix it)3. Output Board missing.I repaired the display thing first, the negative voltage wars bad. at connector j21 pin7 (I manually put minus16v on at pin) and the display came back to live. I found a small defective sot23 diode on the bot side of the motherboard, from u614 pin (vsw) to pin (in), I replaced it with a bav99 diode.I found out that the ad7528jp is not changing his output voltage if I press on the display buttons on the front, I replaced the DA converter and the TL074 opamp next to the DA as well.I placed a lm224 for the tl074, bingo the display is fixed.I searched for an replacement output card but They are very expensive.I searched the net and found a output card from a tester who looks the same from outside it is a "e5515-61183 (3947) vector output 1 or 2" Card.I purchased 2 of them for 26$ each! Perfect, arrived and they fit inside the e4400.Switched on the unit 😱🙌😞.Stay tuned! I post pictures etc.the unit boots and tell me of corse its the wrong card "eeprom dose not mach or simular meening"now i need anyboddy who has such a card with the eeproms to read it out.U801, U804, U805, U806eeprom 2048 x 8- or 1024 x 16-bit organization (93C86)

author: kjk24
author_rank: Regular Contributor
timestamp: December 27, 2017, 07:07:59 pm
content: I readout the serial eeprom u801 and the others too.Only u801 have data all other eeproms are empty.My question, can anyone readout u801 Form a esg e44xx outputcard ?The "e5515-61183 (3947) vector output 1 or 2" outputCard works i use it as it is for now, the error still ocurs. in the future i change the eeprom contense.

author: kjk24
author_rank: Regular Contributor
timestamp: February 25, 2018, 05:15:55 pm
content: the outputcardhere XRay Pics of the second attenuator section of the board.The main defect:2 Pin diods defect, the voltage at the first Pindiode is -6V for HF=off and 0V=HF on.the normal DC Voltage over each Pindiode is +1.6VI changed the Pin Diodes and the Voltage is now +8.2V@20dbm,Alc=off,HF=on,frq=250Mhz,Mod=offwhat is normal i think.

author: kjk24
author_rank: Regular Contributor
timestamp: February 25, 2018, 05:37:05 pm
content: the Attenuator CardFailture:the RPP Relais dont turn on! no output at the output connector.Solution:2 Transistors i think in a bipolar transistor configuration are bad, replaced it and the +5V for the Relais are ok now.the HF Relais switches the HF to the output connector.attached some pics for a working unit.

author: kjk24
author_rank: Regular Contributor
timestamp: February 25, 2018, 06:03:45 pm
content: in the Attenuator Chip 1GM1-4204the pics are not perfect i know, in the circurit is a type of silicone on top of the ceramic board but is not try? its a transparent fluid.i measured with a scope on the HF path without a problem.after re assembling i meldet the Chip with leadfree solder, the chip Attenuate like before.hints.the Chip is not soldered on the board it is socket.the cover of the chip is glued with a verry strong kind of tape, not meldet !