Electronics ATi AIW 9800 PRO problems - Power Delay Relay Circuit needed

I've been through this a few times. All you need is a diode. Certain motherboards and power supplies seem more affected by this. I have a 9700 pro AIW, an A7N8X worked fine, I swapped it out with an NF7 and it didn't work with the 400 watt antec that was on the A7N8X. I tried a 300w antec that worked fine, but a 430 antec would not work. I rma'd the card and they fixed it. Refer to ATI info base 4237. Good PSU's are more affected than crappy PSU's

If you don't want to wait on an rma, the easiest thing to do is put a diode in the 5 volt line that feeds the extra power connector on the graphics card to keep the momentary overvoltage from tripping the PSU. I did this the second time around, it's quick, simple, and it works great. You need a high current low loss diode, I used one from an old power supply, it gets a little warm, it probably wouldn't be a bad idea to use a small heatsink, it was screwed to a heatsink in the power supply.

 

Could someone comment on the post from Turbochris?

Is this a good solution, does it really work? If so, I would like to try this (I have the problem).

I have plenty of old PSU's lying around, but rather limited knowlendge of electronics. So could someone tell me what I need to look for and how to put it together?

Thanks

 

I see that my relay circuit thread is still of interest to people. Since it has been out of use for a while, some of the pics are dead - I'll fix them this morning.

The diode solution would be really simple if it worked, and sounds plausible, however, I have no way of testing it.


Update: I cannot get access to my pictures rignt now - I'll get them all posted by this time next week.

 

Pictures available still? I'm really interested in this circuit, as it's *exactly* what I need for delaying the power-on of my VFD, though it'd need to be adjusted for 5v instead of 12v.

 

Yes, the pictures are still available. First I went on holiday, then I've been having trouble uploading them to my website. I'll try to get them back up this evening - if I fail, mail me and I'll send you all the pictures / schematics / Eagle PCB files in a zip folder.

Is the circuit going into a normal PC, in order to power up the VFD 2-3 seconds after the rest of the PC? If so, you don't need to modify the circuit to do what you need - just connect the VFD (which I assume to be running off 5V) between the +5V and ground outputs of the circuit, leave the +12V output disconnected, and it will work fine.

Otherwise, if you only have +5V available for input to the circuit for some reason, you can change the zener diode for a lower value (eg. 4.2V zener, and play about with the capacitor / variable resistor values to get the circuit to work fine on 5V.

 

Wow, you've nailed it right on the head. This is definitely exactly what I need. I guess if I'd paid closer attention to the pictures of your PCB, I'd have realized that myself! Thanks, this is great.

I'll look for everything tonight. I have Eagle and have all the necessary equipment to build my own PCB. I recently built a custom UIRT2; I integrated some QT110s for power, reset and DVD eject, and a temperature controlled fan controller and a power connector for the VFD. I think I didn't allow adequately for the load of the VFD, as it doesn't seem to work, so instead I'm using 5v off a molex straight from the PSU.

I built that PCB the hard way, with iron-transfer and FeCl etching. I now have photo-etching equipment and some ammon. pers. and this would be a great chance to try it out.

 

Hi cpuwiz, glad the circuit is of use to you. All the pics are mended now, (except the last one of the PCB) and I've fixed the link to the zip archive for the Eagle artwork. If you have any problems, (with the circuit or the links) feel free post here and let me know.

I usually make PCBs that way too. I have a home built UV exposure unit and a second hand bubble etching tank. However, for circuits as simple as this one, I use a system called "Press 'n' Peel Blue". This allows you to print your PCBs onto special film, (using a laser printer), and then iron-on-transfer them onto copper board, ready for etching. Its a bit expensive, but for simple boards (without many thin tracks) then it can save hours.

 

Ha! That's exactly what I use myself; I bought 10 sheets a while ago and have only used two. though it seems to take a couple of tries to get the heat and pressure right. Even then, there's always some tracks that need fixing.

This may be a simple circuit, but I think I'll give the photo thing a try. Thanks again!