Schematics for Varian 3400

[Redi]

I started browsing the forum and it surprised me when I found so much users for Varian 3400. I´m having problem with one of these (power suply overheating) and need the schematics to check some conections. Anyone knows where can I find these schematics? Or service manual?

Thanks,

Redi Siqueira

[HbJ]

Please describe the exact nature of your problem

[Redi]

The cable that goes from power suply to J31 on the mainboard has overheated. I replaced the wire and took the voltage reading (20v) but I don´t know if this is the right. The GC started ok (but the error messages I mencioned at the other post).
Till now, it is working well, but I would like to have a better understanding of the equipment.

Thank you for your interest.

Regards,

Redi

[HbJ]

There is no J31 in any schematics I have.

Please re-check and take a picture so I can see the actual position.

It might be J21 which carries the net voltage.

[Redi]

I sending you a photo of mainboard and signed J31 conector and also a little burned path.
First time I try to put an image here, if you can not see it, please, let me know.



Thanxs,

[HbJ]

I don't see an image, please give the URL.

[Redi]

Link for GC 3400 Mainboard photos:

https://picasaweb.google.com/1003974325 ... directlink

[HbJ]

Well... the part number hints towards a mainboard for a Varian 3600.

The burned path carries one of the terminals of the ignitor voltage for the FID (J 18).

None of my diagrams show a J31 but the visible connected line between J 18 and J 31 on the circuit board carries one terminal of the voltage for TSD no. 2.

[Redi]

HbJ:
Do you know which would be the rigth voltage for the ignitors? Both of them (2 FIDs in the system) are open and I´m thinking if its not related with this conector.

[HbJ]

Open in what way?

If you can't ignite them, it's said connector. According to the specs, it's delivering 3.8 V to the ignitor coils.

[Redi]

The coils are open. The analyst is doing the ignition manually, with an eletric lighter till new ones arrive, but I´m afraid the new ones can burn again if the circuit is not ok. I even thinking in recommend they do not change the ignitor probe and live with the problem till buy a nem GC.

At J31 conector (wires from power suply to conector) I read 20 v !!

[HbJ]

That is okay as J31 is the TSD voltage which is around 18 volts.

J18 carries the ignitor voltage.

[HbJ]

Just a hint: The ignitor voltage must only be present when ignition is demanded. If it's stuck on you have an electrical problem (just saying).

[Redi]

OK, HbJ,
The system is running without the ignition (I´m using an external ignitor) and seems is ok. I´m still afraid to replace the ignitor for a new one and burn it again.

Thanxs a lot.

[HbJ]

OK, HbJ,
The system is running without the ignition (I´m using an external ignitor) and seems is ok. I´m still afraid to replace the ignitor for a new one and burn it again.

Thanxs a lot.

That's fair Have fun with your 3400!