Si570 current

General discussion and support for the Peaberry SDR V2.

Si570 current

Postby Yury » Wed Dec 10, 2014 7:44 pm

I have completed receiving part only. The receiver works 5-7 minutes and stops.
Investigation indicated strange behavior of Si570.
After switch on - the Si570 (U9) current 100 mA, in 20-30 sec it becomes 300 mA at once (as trigger). I picked up 3.3V legs 7 U11 and U10 to rest only U9.
The receiver works 5-7 minutes only. I think it is due overheating Si570.
I think I need to replace Si 570.
Has anybody other ideas?
Yury
 
Posts: 3
Joined: Wed Dec 10, 2014 7:06 pm

Re: Si570 current

Postby TerryFrench » Wed Dec 10, 2014 10:24 pm

I do not have any technical help to offer here, but I built a Peaberry myself.
Basically, I'd check all soldering connections you have so far with a 10x magnifier (loupe) before thinking about replacing any part. It's surprising how well some parts support the various issues we have when we solder them. (I'm thinking about you PSOC).
TerryFrench
 
Posts: 106
Joined: Thu Oct 17, 2013 3:56 am
Location: Redmond, WA USA

Re: Si570 current

Postby Yury » Thu Dec 11, 2014 8:08 am

I checked all soldering with magnifier and mechanical. I could not find mistakes. Additionally I disconnected U14 from 5V to avoid loading Si570. Si570 had contact only to U10 “SCL” and “SDA” points. However, these points are connected to 3.3V through 4.99 k (checked). It cannot give +200 mA.
I disconnected Si570 from 3.3V and resoldered removed points. Without Si570 I had steady current near 50 mA.
Yury
 
Posts: 3
Joined: Wed Dec 10, 2014 7:06 pm

Re: Si570 current

Postby AE9RB » Thu Dec 11, 2014 11:29 pm

It doesn't sound right that a Si570 would fail in this way. It's more likely there's a solder bridge under the part or the alignment is poor. After a brief warm up a short is created from thermal expansion.
73 David AE9RB
AE9RB
Site Admin
 
Posts: 511
Joined: Thu Nov 15, 2012 5:27 am
Location: Portland, Oregon, USA (CN85ql)

Re: Si570 current

Postby Yury » Sat Dec 27, 2014 8:58 am

Si570 has been replaced now. Current and rcvr are OK. :D
Yury
 
Posts: 3
Joined: Wed Dec 10, 2014 7:06 pm


Return to Peaberry SDR V2

Who is online

Users browsing this forum: No registered users and 2 guests

cron