peavey XR684 cooling fan not working

[guitarman51]

hi - i've managed to get my XR684 working again thanks to your expert advice
It sounds great buti now have a question regarding the cooling fan hence the new post

The cooling fan is not running when i switch ON is that correct?
I've been testing the amp in my garage and ambient temps are around 8c

I measure 5.5vdc at P01 - P02 with fan connected and
12.5vdc with fan unplugged
I have assumed that the thermistor resistance will increase with the heatsink
temperature and subseqently switch the fan on, is that correct?

SchematicPeavey XR684 schematic.pdf attached
Thank you

[nickb]

The link is dead. The dreaded "clear.gif" bug strikes again. Try zipping it?

Correction: Not clear.gif but unresponsive link instead.

[nsubulysses]

You know, in certain scenarios I have downloaded the dreaded clear GIF from this site, but then when I open the file in photoshop it is visible. Anybody else try this

[g1]

Attached is the zip of the schematic.
TR01 & TR02 (A6 area of schem) are the thermistors for the fan. Heating them up with a hair dryer or something should get the fan to turn on. Or getting the amp hot running into a load etc.

[guitarman51]

thanks for that
i had assumed that the fan would run on startup ?

[Enzo]

Some circuits do, some don't. If in doubt, I use a heat gun on the sensor to find out if it is working.

[Jazz P Bass]

You know, in certain scenarios I have downloaded the dreaded clear GIF from this site, but then when I open the file in photoshop it is visible. Anybody else try this

Now THAT is interesting!

Unfortunately, I do not have Photoshop.

[nsubulysses]

actually maybe I am mistaken. On the ones it worked with it listed the real name of the schematic but when opened in a preview mode it was blank. then opening in photoshop it was visible.

I tried with this one and when it DLs it is literally called "clear.gif" and does not work

Could just be a different scenario altogether

[g1]

Yeah, "clear.gif" does not download, and if you do, it's only 43 bytes.
Must have been something else.

[Jazz P Bass]

I hate when Google shows a preview of the file & then you click on it and....

It's blank.