B777

To all TEMS users,

Recently we had two cases of engine shutting down without cool-down cycle and no error messages. This is very strange and unusual. One possibility is that the TEMS temporarily lost power and reset itself which sounded like a poor power connection. We traced the problem to the contact points at both ends of the Fuse Holder. You may not have experienced the problem but please check and make sure that you have good contact at these ends. The soldered wires at each ends may have come loose after repetitive pulls while checking the fuse or bundling up the wires during installation. Eliminating the fuse box is not a good solution since it is there to protect the ecu board in case of faulty power connection. We are looking at a more sturdy fuse holder than the one being used. We will rectify the problem prior to any future shipment.

Recommended procedures:

1. Open the Fuse Holder and check both ends of contact points.
2. Make sure that the wires are well soldered and clamped.
3. Stretch the preloaded spring a bit further to increase contact pressure.
4. Reassemble the Fuse box
5. Connect the GDT and power up the TEMS.
6. Verify power connection thru the GDT while moving around both ends of the Fuse Holder.
7. If you experience bad connections, please replace the Fuse Holder.

It is not cost effective to send the unit back to your reps or to PST just for the replacement of a bad Fuse Holder. You can find these Fuse Holder at most electronics shops in various types. Please replace it with the same or at least 20Amp tolerance for the 15Amp Slow-Blow fuse. For engines under warranty, we will find the best way to reimburse the replacement expenses. (edited April 4th, 2005)

Thank you.
Kraivuth S.

Kelly W

My Feedback: (2)

Hi Everyone,

Here is the product I am using to repair the set of ECU's Kraivuth spoke of above: [link=http://www.radioshack.ca/estore/Product.aspx?language=en-CA&catalog=RadioShack&category=Fuses&product=27012 13]20A Max Blade Fuse Holder[/link] As stated, it has a 20Amp max capacity but should have a 15Amp fuse installed. I don't think the current consumption ever goes above ~9 Amps in the worst case, so 15 should give a suitable safety factor over normal operation, yet protect from a short. Since virtually everyone is within reach of a Radioshack, here are a few useful links.

Canadian Customers:
[link=http://www.radioshack.ca/estore/Product.aspx?language=en-CA&catalog=RadioShack&category=Fuses&product=27012 13]20 Amp max, blade fuse[/link]
[link=http://www.radioshack.ca/estore/Product.aspx?language=en-CA&catalog=RadioShack&category=Fuses&product=27012 34]30 Amp max, blade fuse[/link]
[link=http://www.radioshack.ca/estore/Product.aspx?language=en-CA&catalog=RadioShack&category=Fuses&product=27012 37]30 Amp Max, mini blade fuse[/link]

US Customers:
[link=http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CT LG%5F011%5F004%5F004%5F000&product%5Fid=270%2D1213]20 Amp max, blade fuse[/link]
[link=http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CT LG%5F011%5F004%5F004%5F000&product%5Fid=270%2D1234]30 Amp max, blade fuse[/link]
[link=http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CT LG%5F011%5F004%5F004%5F000&product%5Fid=270%2D1237]30 Amp max, mini blade fuse[/link]

I'd recommend soldering the new holder directly to the Deans Ultra connector and applying a new heat shrink cover, then splicing the other end to the cable that's already connected to the switch. Customers may choose to resolder the other end directly to the switch, but care must be taken not to overheat the switch and distort the body. For that reason, I recommend cutting the existing wire a few inches from the switch and simply joining the new fuse holder to it, then covering it with and appropriate piece of heat shrink.

Its important to note that customers should not panic and assume that every fuse holder needs to be changed, as there are several hundred ECUs like this happily functioning around the world today, almost all of them with the old fuse holder. So far to our knowledge, no PST powered aircraft has had a forced landing or worse yet crashed due to a faulty fuse holder. By notifying all customers and asking them to test their systems, we hope to maintain that statistic.

If anyone has any questions, please don't hesitate to PM me.

Thanks,
Kelly W

B777

Kelly's recommendations are appropriate and should be followed. For those having difficulty in reaching Radio Shack, your local electronics or auto spare parts shops should carry 20Amp capacity or more fuse holder. Like Kelly has stated, these are the only two TEMS with faulty Fuse Holder and we have already rectified the issue on all TEMS in stock.

Kraivuth S.

wd40

My Feedback: (81)

I would like to thank you guy's for the fix to my two new PST'S 600R Turbine ecu's I have now put some flights on them and thay are running great.



Thanks
Mike Grant

B777

This is the new TEMS fuse holder that will be fitted for all new deliveries or service engines. The holder is made in Japan and provides secure connection between the wires and the fuse. The fuse is securely contained inside a protective case which is very rugged when closed.