Old 31-07-2010, 11:44 AM
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mldee (Mike)
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Join Date: Aug 2008
Location: Near Warwick, Qld, Australia
Posts: 516
Urgent heads-up for QHY8 Pro owners

I have been having non-stop problems with erratic TEC cooling function on my QHY8 Pro purchased here on IIS. It would appear that others may also have experienced this. My previous QHY8 was fine.

USB, power, close cables, drivers, PC, all the usual suspects tried to no avail.

To cut a long story short, after exhausting local avenues of assistance, including sending it to the sole Australian dealer, and eliminating as many potential causes as possible, I contacted the China QHYCCD help desk last night at 6pm. They had replied by 9pm, on a Friday night no less, with a fix that works! It's turned a cantankerous cow of a camera into a docile imaging delight.

They admitted there was a TEC (cable) problem on QHY8 Pro's made before May 2010, and gave me a fix (change two 10K resistor values on the rear connector board to 2.2K). Correspondence is attached, including their pdf resistor fix instructions.

TIP: I could not buy smd resistors on a Saturday morning, so in the hope that the function was not overly frequency sensitive, tried tacking two small 2.7K metal film resistors from Jaycar in parallel with the 10K smd's as per the pdf. Works just fine. More than fine, just great. No overshoot, no hiccups, no glitches, just goes to set temp and sits there. Been running for two hours now at -21c 70% power from Ezcap 1.18 temp graph, after initial hour at -15c. Nebulosity works fine too.

Warning: needs a steady hand, a small soldering iron and a magnifying gadget. If you don't feel confident, contact Theo, ...he may even do it under warranty..... or get your local electronics service shop (do they still exist?) to do it. The pdf instructions are quite clear.

Hope this helps any other frustrated souls out there.
Attached Files
File Type: txt QHYCCD help desk email 100730.txt (2.3 KB, 32 views)
File Type: pdf QHY8PRO FAN&TEC control modification.pdf (96.0 KB, 54 views)
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Old 01-08-2010, 02:10 AM
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Join Date: Dec 2005
Location: Melbourne
Posts: 1,121
Mikes correct, the actual issue found was that the new longer length multi pin cable were changed and was causing issues to some older QHY-8 Pro cameras. This extra length caused some hickups.
So the old tale, "Size Does Matter".
But as Mike said, there is a now easy fix released, and if you ever have your cable changed with the longer one, take note.
This is protected under your local warranty, regardless if its out of warranty too.

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Old 31-10-2010, 09:43 AM
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peter_4059 (Peter)
Big Scopes are Cool

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Join Date: Jun 2007
Location: Brisbane
Posts: 4,252

Has this issue with your camera been fully resolved now? Mine started playing up in a similar way yesterday after months of normal operation. I don't have the long cable (mine is 2.5 m) but the symptoms sound similar.

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