Search found 649 matches

by Icky
Mon Nov 12, 2018 10:03 pm
Forum: PSU (power supplies)
Topic: R205 100 ohm resistor in SR98 starting to get hot and smell
Replies: 7
Views: 158

Re: R205 100 ohm resistor in SR98 starting to get hot and smell

And here are the bags of fun that are going towards this make over

One Exxos recap kit and a bunch of metal film resistor replacements:
IMG_3271.png
IMG_3271.png (755.51 KiB) Viewed 35 times
by Icky
Mon Nov 12, 2018 10:00 pm
Forum: PSU (power supplies)
Topic: R205 100 ohm resistor in SR98 starting to get hot and smell
Replies: 7
Views: 158

Re: R205 100 ohm resistor in SR98 starting to get hot and smell

Well I tried to start recapping this PSU over the weekend but got caught up in the STF Remake Reset Circuit fun viewtopic.php?f=19&t=1234

So I thought I would post a pic before this bad boy gets a make over.

Before:
IMG_3270.png
IMG_3270.png (1023.92 KiB) Viewed 36 times
by Icky
Mon Nov 12, 2018 7:19 pm
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

EDIT: I'd say this one is the best candidate to try next... https://uk.farnell.com/microchip/mic6315-29d4uy-tr/reset-active-low-2-93v-20ms-4sot143/dp/2510415?st=MIC6315 Even though I detest evil bay.... https://www.ebay.co.uk/itm/5pcs-SOT-143-SOT-143R-SMD-DIP-Adapter-Breakout-Pinboard-Dual-sided-4-...
by Icky
Mon Nov 12, 2018 7:03 am
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

exxos wrote:
Mon Nov 12, 2018 12:27 am
http://www.ti.com/product/TPS3808/technicaldocuments

Looks good.. But output drive seems a bit wimpy :roll:

I guess a small MOSFET could be used to beaf it up.. Still smaller than a TTL chip..
Did you look at these https://www.st.com/en/reset-and-supervi ... m1816.html
by Icky
Mon Nov 12, 2018 12:19 am
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

exxos wrote:
Mon Nov 12, 2018 12:16 am
I will have a look for a better reset chip tomorrow.. There are things like the LP3470 , must be some chip out there which has a good drive current so can do away with the LS05 all together..
That would be great if that is the case. The less chips the better.
by Icky
Mon Nov 12, 2018 12:10 am
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

exxos wrote:
Mon Nov 12, 2018 12:03 am
Aye, doesn't seem like its going to behave :( wonder if the 555 circuit could be rejigged to give a inverted output :shrug:
Yep 47K made no difference still white screen :(

Definitely feel like :headbang: with this circuit. I tried out so many combinations today.
by Icky
Mon Nov 12, 2018 12:00 am
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

Hmm - with 100nF and 470K white screen and no boot. Reset button stays on white screen no boot or flicker of reset. Damn... Try 47k.. Its a crazy one this one trying to find the right combination. This is going to be the last one tonight. Am all reset out today. Didn't get anywhere near my recap ta...
by Icky
Sun Nov 11, 2018 11:45 pm
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

Hmm - with 100nF and 470K white screen and no boot. Reset button stays on white screen no boot or flicker of reset.
by Icky
Sun Nov 11, 2018 11:11 pm
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

What capacitor value do you have in at the moment 22uf ? and 1K ? I think the problem is the switch isn't discharging the capacitor fast enough... even when it is, the reset pulse low is just to short... Try something like 100nF and 470K any higher values on either and it will malfunction (accordin...
by Icky
Sun Nov 11, 2018 9:14 pm
Forum: STF REMAKE PROJECT
Topic: RESET circuit tweaks
Replies: 104
Views: 714

Re: RESET circuit tweaks

I'm starting to think that the 555 circuit is probably the best one so far. Here is a video of the board booting with the simple circuit and then reseting and on the second reset it goes into the strange frozen bigger desktop and takes several resets to get it to reboot. Apologies for the shaky vide...