This Schumacher 1042A-PE battery charger stopped functioning today. It
seemed to work for a little while but when I noticed the car battery's voltage wasn't slowly increasing after performing a 2 amp charge for 2
hours, I checked the voltage at the charger's cables and it was 0 volts.
The continuity of the switches and cables were all good. I did find a
power semiconductor which I could not identify, BTW70-200SN. I looked in
an old ECG cross-reference book and the closest match was for a
BTW69-800 which is an SCR in a TO-218 package. The package seems to
match the device I'm looking for. I made some measurements with my
Simpson 464 DVM on the 2k ohm scale. Pins 1 and 3 measure 38 ohms
regardless of test lead polarity. All other combinations of continuity measure open circuit. In circuit, pins 1 and 2 are soldered together.
Any idea what this component is or how to test it?
This Schumacher 1042A-PE battery charger...
On Fri, 19 Aug 2022 19:39:03 -0700, David Farber
<farberbear.unspam@aol.com> wrote:
This Schumacher 1042A-PE battery charger...
Are you sure about that model number? Methinks that SE-1052A-PE is
more likely.
On 8/19/2022 10:25 PM, Jeff Liebermann wrote:
On Fri, 19 Aug 2022 19:39:03 -0700, David Farber
<farberbear.unspam@aol.com> wrote:
This Schumacher 1042A-PE battery charger...
Are you sure about that model number? Methinks that SE-1052A-PE is
more likely.
Youthinks correctly! It is a 1052A.
On Fri, 19 Aug 2022 23:30:27 -0700, David Farber
<farberbear.unspam@aol.com> wrote:
On 8/19/2022 10:25 PM, Jeff Liebermann wrote:
On Fri, 19 Aug 2022 19:39:03 -0700, David Farber
<farberbear.unspam@aol.com> wrote:
This Schumacher 1042A-PE battery charger...
Are you sure about that model number? Methinks that SE-1052A-PE is
more likely.
Youthinks correctly! It is a 1052A.
Unfortunately, that didn't help when looking for information using
Google search. I couldn't find anything on the SE-1052A-PE except the
owners manual. No schematics or articles on repairing it. No photos
of the inside. ><http://powertool.manualsonline.com/manuals/mfg/schumacher/se_1012d_se_1052.html>
Notice that the user manual covers a range of models which probably
share similar circuitry. Try searching for the other models.
SE-1010-2, SE-1012D, SE-1052, SE-1250
David Farber wrote:
=============
This Schumacher 1042A-PE battery charger stopped functioning today. It
seemed to work for a little while but when I noticed the car battery's
voltage wasn't slowly increasing after performing a 2 amp charge for 2
hours, I checked the voltage at the charger's cables and it was 0 volts.
The continuity of the switches and cables were all good. I did find a
power semiconductor which I could not identify, BTW70-200SN. I looked in
an old ECG cross-reference book and the closest match was for a
BTW69-800 which is an SCR in a TO-218 package. The package seems to
match the device I'm looking for. I made some measurements with my
Simpson 464 DVM on the 2k ohm scale. Pins 1 and 3 measure 38 ohms
regardless of test lead polarity. All other combinations of continuity
measure open circuit. In circuit, pins 1 and 2 are soldered together.
Any idea what this component is or how to test it?
** Could be an SCR maybe.............
With a 1A, current limited, DC supply of about 12 V, + on the anode - on the cathode, apply a brief pulse of +50mA at +1.5V to the gate with - on the cathode as well. The 12 volt supply should the be clamped at about +1.2V.
You 38 ohm readings are normal.
..... Phil
On Sat, 20 Aug 2022 00:09:28 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:
On Fri, 19 Aug 2022 23:30:27 -0700, David Farber
<farberbear.unspam@aol.com> wrote:
On 8/19/2022 10:25 PM, Jeff Liebermann wrote:
On Fri, 19 Aug 2022 19:39:03 -0700, David Farber
<farberbear.unspam@aol.com> wrote:
This Schumacher 1042A-PE battery charger...
Are you sure about that model number? Methinks that SE-1052A-PE is
more likely.
Youthinks correctly! It is a 1052A.
Unfortunately, that didn't help when looking for information using
Google search. I couldn't find anything on the SE-1052A-PE except the
owners manual. No schematics or articles on repairing it. No photos
of the inside.
<http://powertool.manualsonline.com/manuals/mfg/schumacher/se_1012d_se_1052.html>
Notice that the user manual covers a range of models which probably
share similar circuitry. Try searching for the other models.
SE-1010-2, SE-1012D, SE-1052, SE-1250
Bingo, except that there's no SCR in the schematic. <https://www.fixya.com/support/t25414948-wiring_diagram_switch_se_1052> <https://www.fixya.com/support/t7882270-looking_wirring_diagram>
Kinda looks like just the PCB wiring and not the complete unit. This
is from a different charger (SE-1275A) that MIGHT have the same
wiring. How close are the drawing and schematic to what you have?
Getting back to the testing of the SCR (if it is an SCR), how do I
identify anode, cathode, and gate?
David Farber wrote:
==============
Getting back to the testing of the SCR (if it is an SCR), how do I
identify anode, cathode, and gate?
https://au.mouser.com/datasheet/2/389/sgsts33425_1-2282554.pdf
... phil
David Farber wrote:
=============
This Schumacher 1042A-PE battery charger stopped functioning today. It
seemed to work for a little while but when I noticed the car battery's
voltage wasn't slowly increasing after performing a 2 amp charge for 2
hours, I checked the voltage at the charger's cables and it was 0 volts.
The continuity of the switches and cables were all good. I did find a
power semiconductor which I could not identify, BTW70-200SN. I looked in
an old ECG cross-reference book and the closest match was for a
BTW69-800 which is an SCR in a TO-218 package. The package seems to
match the device I'm looking for. I made some measurements with my
Simpson 464 DVM on the 2k ohm scale. Pins 1 and 3 measure 38 ohms
regardless of test lead polarity. All other combinations of continuity
measure open circuit. In circuit, pins 1 and 2 are soldered together.
Any idea what this component is or how to test it?
** Could be an SCR maybe.............
With a 1A, current limited, DC supply of about 12 V, + on the anode - on the cathode, apply a brief pulse of +50mA at +1.5V to the gate with - on the cathode as well. The 12 volt supply should the be clamped at about +1.2V.
You 38 ohm readings are normal.
..... Phil
Questions about the test setup:
1. For my 1A, current limited, DC supply, I was going to using my bench
power supply and set the current limiter to 1A
2. For the brief pulse, I was going to use a 1.5 volt, AAA battery.
Since there's a 38 ohm (internal resistor?) connection between the
cathode and gate, does that mean the 1.5 V pulse will be automatically limited to about 40mA?
3. How do I clamp the 12V supply to +1.2 volts?
David Farber wrote:
=============
Questions about the test setup:
1. For my 1A, current limited, DC supply, I was going to using my bench
power supply and set the current limiter to 1A
** Good.
2. For the brief pulse, I was going to use a 1.5 volt, AAA battery.
Since there's a 38 ohm (internal resistor?) connection between the
cathode and gate, does that mean the 1.5 V pulse will be automatically
limited to about 40mA?
** It can be much higher as the resistor is in parallel with the device gate and cathode.
3. How do I clamp the 12V supply to +1.2 volts?
** The SCR will do that when it triggers on - if it is working.
..... Phil
** It can be much higher as the resistor is in parallel with the device gate and cathode.
3. How do I clamp the 12V supply to +1.2 volts?
** The SCR will do that when it triggers on - if it is working.
Assuming the SCR is working and it's clamping properly, where am I to
measure the 1.2 volts? The anode is connected directly to the 12 V
supply and the cathode is grounded. That leaves the gate. Will it
measure 1.2 V after I remove the 1.5 V supply?
David Farber wrote:
================
** It can be much higher as the resistor is in parallel with the device gate and cathode.Assuming the SCR is working and it's clamping properly, where am I to
3. How do I clamp the 12V supply to +1.2 volts?
** The SCR will do that when it triggers on - if it is working.
measure the 1.2 volts? The anode is connected directly to the 12 V
supply and the cathode is grounded. That leaves the gate. Will it
measure 1.2 V after I remove the 1.5 V supply?
** Read my first post again.
SCRs, once triggered, conduct large currents with small voltage drops.
..... Phil
David Farber wrote:
================
** It can be much higher as the resistor is in parallel with the device gate and cathode.Assuming the SCR is working and it's clamping properly, where am I to
3. How do I clamp the 12V supply to +1.2 volts?
** The SCR will do that when it triggers on - if it is working.
measure the 1.2 volts? The anode is connected directly to the 12 V
supply and the cathode is grounded. That leaves the gate. Will it
measure 1.2 V after I remove the 1.5 V supply?
** Read my first post again.
SCRs, once triggered, conduct large currents with small voltage drops.
..... Phil
Phil Allison wrote:
** Read my first post again.
SCRs, once triggered, conduct large currents with small voltage drops.
Finally got around to testing the SCR and it works perfectly.
other active components other than the power supply diodes are the two
IC's, LM2901 and LM2903.
David Farber wrote:
Phil Allison wrote:
** Read my first post again.
SCRs, once triggered, conduct large currents with small voltage drops.
Finally got around to testing the SCR and it works perfectly.
** Yep - expected that.
The only
other active components other than the power supply diodes are the two
IC's, LM2901 and LM2903.
** I see a TO92 pak transistor near the SCR.
Lotta resistors about too.
Dead easy to check them for opens.
.... Phil
The only
other active components other than the power supply diodes are the two
IC's, LM2901 and LM2903.
** I see a TO92 pak transistor near the SCR.
Lotta resistors about too.
Dead easy to check them for opens.
.... Phil
I removed the 8-pin DIP op amp
and tested one of the amps as described here:
By the way, many of the voltage +/- inputs for the quad and dual op amps
when measured in-circuit were amiss.
David Farber wrote:
=================
I removed the 8-pin DIP op amp
The only
other active components other than the power supply diodes are the two >>>> IC's, LM2901 and LM2903.
** I see a TO92 pak transistor near the SCR.
Lotta resistors about too.
Dead easy to check them for opens.
.... Phil
** What op-amp?
FYI the LM2903 is a *comparator* so is the LM2901.
https://www.st.com/resource/en/datasheet/lm2903.pdf
> and tested one of the amps as described here:
** Irrelevant.
> By the way, many of the voltage +/- inputs for the quad and dual op amps
when measured in-circuit were amiss.
** Normal for comparators.
Your circuit is * non linear * and uses switching to control the SCR and hence output of the charger.
...... PhilI missed that point. I will reconfigure my test circuit and report back...
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