help with identifying an IC in Tektronix AWG2020 arb generator - Page 1
Forum section: electronics / testgear

author: analogRF
author_rank: Super Contributor
timestamp: January 15, 2018, 01:33:57 pm
content: Long story short, I am in the middle of repairing an AWG2020 arb generator I got very cheap on ebay. I have restored a lot of things (all SMD electrolytics leaking all over the boards, PCB traces, pads, and the dead ADC chip) but I now have error 630 which according to TeK support guy means "5 X mag DA offset adjust fail". I know for sure (tested multiple times) that the big wideband CFA op-amp CLC561AI is dead. I am planning to replace it with a THS3001 or THS3091. I will install it on a small adapter board and connect the pins by wires and change the feedback resistors to have the same 20dB gain and 50 ohm I/O impedance like the original amp.But that amplifier is only switched into the signal path (ahead of the attenuators) for amplitudes larger than 500mVpp. Below this amplitude that op-amp is completely cut off from the signal path by two relays. So I dont know if that is related to the error 630 or not.However, I have two more suspects one of which I cannot even identify what it is. One is an 8 pin SOIC marked 842 (there are two of them. I suspect the lower one which has -15V supply) By the looks of it and the circuitry around it, I am pretty sure it is a UPC842 dual op-amp. It definitely looks like a chip by NEC. It is not in the signal path and certainly it does something else (perhaps used in auto calibration of amplitude or offset).The other suspect is another 8 pin SOIC marked as CL404A. There are 2 of them on the analog board. I cannot find out what it is. I have looked everywhere and there is no information about this IC. I don't think it's custom made. It has no tektronix number on it and seems to be from a third party. Anybody has any idea what this IC is?thanks

author: tautech
author_rank: Super Contributor
timestamp: January 15, 2018, 05:28:29 pm
content: Find the Tek part # from the manuals and cross ref it here:http://www.sphere.bc.ca/test/tekequiv.htmlIf it's not in that short list check the link at the bottom right of this page.(Sphere ask for it not be linked online.)

author: analogRF
author_rank: Super Contributor
timestamp: January 15, 2018, 05:35:34 pm
content: Quote from: tautech on January 15, 2018, 05:28:29 pmthere is no tek P/N. The ic is marked CL404A and the manual does not have a parts list.

author: tautech
author_rank: Super Contributor
timestamp: January 15, 2018, 05:47:30 pm
content: Quote from: analogRF on January 15, 2018, 05:35:34 pmBugger !That won't make things simple. A quick look online indicates these have a tie up with Sony. Did they release an equivalent model ?Seems everyone's looking for a schematic.

author: analogRF
author_rank: Super Contributor
timestamp: January 15, 2018, 08:57:07 pm
content: I don't know about the Sony but, yes, I badly needed the schematics and I even contacted Tektronix but he simply said "these were repaired on board level and there is no schematics!"Anyways, I have played around with that analog board A2 for many hours and I have a good understanding of the signal path but still there is so much I don't know specially how exactly the calibration of amplitude and offset takes place. There are 3 DACs and an ADC on board.Anyways, that CL404A has been bugging me for the whole time....no idea what it is. It is not a dual opamp or at least not one with a regular pinout. because the circuitry around it does not correspond to popular pin connection of dual opamps...

author: nctnico
author_rank: Super Contributor
timestamp: January 15, 2018, 09:06:08 pm
content: Better post a picture. Maybe there are other markings on the package. In some cases it is not clear what is the device number and date/manufacturer code.

author: analogRF
author_rank: Super Contributor
timestamp: January 15, 2018, 10:25:37 pm
content: here is a picture. There is also a JE215 below the CL404A but I could not find any thing on that eithernow that we are at it, can someone please tell me what exactly are those elements I marked from 1 to 6and how I can read their values? I think they are resistors but what kind? #4 has a dot on it, too, like a diode but it measures like a resistor in circuit.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: January 15, 2018, 10:35:27 pm
content: Quote from: analogRF on January 15, 2018, 05:35:34 pmAre you sure that it is not a CLC404 respectively version thereof?

author: nctnico
author_rank: Super Contributor
timestamp: January 15, 2018, 11:49:54 pm
content: A CLC404A seems to match the pinning.The other parts may be laser trimmed resistors.

author: analogRF
author_rank: Super Contributor
timestamp: January 16, 2018, 01:14:07 am
content: but as you see in the picture, it is CL404A.Since the high speed high output op-amp on the unit was CLC561IA from comlinear, it kinda makes sense that this one is CLC404I will go with that in my troubleshooting to see how it turns out...thank you guys.