Hi Tom,
Thx for the info. Now ordered 3 pcs. waiting 4 a couple days...
Tjeenz
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--- In TekScopes@..., "Tom Jobe" <tomjobe@...> wrote:
There are two Chinese sellers on eBay who say they have the CA3102.
Another thought... the 2213A, 2215A, 2235, etc. all have three of those CA3102 chips on the mainboard.
Is there any chance of someone in your part of the world having a broken 22xx with some CA3102?
The part is not worth much, but the shipping to Thailand costs a lot.
tom jobe...
----- Original Message -----
From: tjeenz
To: TekScopes@...
Sent: Saturday, September 29, 2012 2:34 AM
Subject: [TekScopes] Re: 2213 no trigger
Hi David,
After waiting for one week for the ca3102, I found out it is not available here (thailand, bangkok area). I checked the internet but come out at companies who want to have minimum order of 150usd.
amazon lists them for 8 usd and shipping around 20 usd. maybe you know of a cheaper seller/location?
tjeenz.
--- In TekScopes@..., David <davidwhess@> wrote:
>
> On Mon, 24 Sep 2012 10:43:12 -0000, "tjeenz" <tjeenz@> wrote:
>
> >I removed u460. (ca3102 from rca). it is broken (20ohm between 1 and 14 in both directions)
> >also i found a diode connected on the top to pin 12. i couldn't detect pin 12 in the schematics... now start looking for a ca3102
>
> On Mon, 24 Sep 2012 08:50:17 -0000, "tjeenz" <tjeenz@> wrote:
>
> >> Voltage U460 pin3 and 9 is -8.6V, R456 is ok.
> >> pin 1 and 8 are 3.5V not 2.2
>
> That fits with pin 1 being 3.5 volts instead of 2.2 volts. The low
> resistance between the collector and base is pulling that node up via
> the high output of U480C.
>
> Pin 2 and pin 10 at about 0.0 volts while pin 3 is -8.6 volts suggests
> that the emitters of U460E and U460B is open as well.
>
> Pin 12 and pin 5 are connected internally to the substrate. The
> CA3102 is built on a junction isolated process so the substrate
> connects to each transistor via a diode which is reverse biased to
> provide isolation.
>
> >> u460 is unfortunately not on a socket.
>
> When replacing U460, I would cut the collet pins out of an IC socket
> and individually install them into the PC board to make a low profile
> socket for the new IC.
>
>
>
> >> To access u460 and area, i see i have to remove some components. I will start on that a.s.a.p. but a question: some loose contact in the timebase switch. sometimes it generates only half screen image when i move with that knob. is that the pot-meter in the middle?
>
> From what I remember of the 2213, the timebase switch uses a different
> and unreliable design from the other 22xx series oscilloscopes.
> Someone else may have suggestions for repairing it.
>
