C-Scope CS1200XD schematic

[nalag46]

If anyone can help with info on the above schematic it would be most appreciated.
Many thanks.

[kt315]

can you give pics of the board? many thanks

[nalag46]

Hi, It has a power supply problem. The circuit is powered by a 12v battery supply. At the power switch, the 12v is present and feeds a 5v positive voltage regulator but its output is measured at +11v. instead of +5v. There is another 5v negative regulator and the same applies there. I have replaced the first 5v. ic but is has not made any difference and a cold test of the other larger 5v negative does not show any signs of been damaged. With a double sided pcb and so many ICs, its not only time consuming but extremely difficult to follow any test pattern.
I am attaching pics of the pcb.

[nalag46]

Any thoughts about this?

[kt315]

can you send me High resolution pics into email? your light is good but i suggest to do
pics under sun at open air. we are not prof cameramen having a kit of light sources but light conditions will be near to good then.


[email protected]

[a7mdrat]

[QUOTE = nalag46؛ 296161] أي أفكار حول هذا؟ [/ QUOTE]

can you send me better pictures please
qedqad@gmail.com

[nalag46]

It is a double sided circuit board which is not easy to photograph in detail. Would you be able to offer any recommendations or likelihood of fault, or are you just looking for the board's component layout?

[kt315]

look cscopex schematic in C-SCOPE folder. no sch for 1220XD but i see a similarity. anyway you can print it and draw yours
measuring links by tester.

[kt315]

can you do Part List? i give an example as i see/present this yours home work.

[kt315]

U2 4053
U4 TLC272
U5 4053
U6 TLC272
U7 CA3140
U8 CA31
U LM339
U9 LM358
U10 4013
U11 4053
U14

[kt315]

I am attaching some pictures (best I can manage) of different parts of
the circuit board to cover most of the components on it. I have found
that after replacing the + 5V Voltage Regulator U12, the output now with
a power

supply of 9V or 12v (this model is supposed to accept rechargeable and
alkaline batteries) varies between 6.6v and 7.5v at test point + 5V on
the board. This voltage is present at the input of all the chips
except for chip U14 (right behind the disc. pot at the front of the
board). This is a low power TLC555 timer and reads 11.5v at all the 7
pins except for the ground pin no.1. Could this be the fault I am
looking for?

abnormal but i do not see as you connect a tester. to measure impulse signal by trivial tester is unnormal, nonsense.
you have to use oscilloscope.

There is a protection diode (soldered across the pins at the back of
the board) but it's not damaged. I am also checking the pair of
transistors BC213 and BC184 feeding into it but I am hesitant about removing

components on a double sided board unless I am absolutely sure they are
dud. What do you think?

i still do not see whole part list of IC's. do not know what is U12. i grasp for what TLC555 is.
maybe for negative voltage power source or frequency modulation, can not understand.
luck information. the board in your hands, not in mine.

[kt315]

n46 can not write in forum, i will retranslate his emails

Hello again,

The thread on Geotech does NOT let me reply. I don't know why?

Components list:
U1-TLC272, U2-4053, UC-3LM339, U4-TLC272, U54053, U6-TLC272, U7-CA3140, U8-CA3140, U9-LM358, U10-4013, U11-4053, U12-7805. U13-7905, U13-TLC555.

Q1-BC184, Q2-??, Q3-J113, Q4-BC184, Q5-BC184, Q6-BC184, Q7-BC184- Q8 BC636, Q9-BC184, Q1O-BC214.

D1-4148, D2-4148, D3-4148, D4-4148, D4-ZENER 7V, D5-4148, D6-4148, D7/D8-BAT-BLUE?, D9/D10-4148, D12-4148.

ELEC. CAPS. CA18-100UF, CA20-10UF, CA21-100UF, CA30/31-200UF.

All Transistors, diodes and caps. have been tested (in circuit) no damage.

[kt315]

revised
U1 TLC272
U2 4053
U3 LM339
U4 TLC272
U5 4053
U6 TLC272
U7 CA3140
U8 CA3140
U9 LM358
U10 4013
U11 4053
U12 7805
U13 7905
U13 TLC555

Q1-BC184
Q2-??
Q3-J113
Q4-BC184
Q5-BC184
Q6-BC184
Q7-BC184
Q8 BC636
Q9-BC184
Q1O-BC214.

D1-1N4148
D2-1N4148
D3-1N4148
D4-1N4148
D4-ZENER 7V
D5-1N4148
D6-1N4148
D7/D8-BAT-BLUE Schottky?
D9/D10-1N4148
D12-1N4148.

CA18-100uF
CA20-10uF
CA21-100uF
CA30/31-200uF

[kt315]

Anatloy. U13 is Voltage Reg. L7905 and this is a new one I have fitted. U14 is the timer TLC555. There is only one TLC555 and the problem has to be between U13 and U14.

The components involved in this part of the circuit are D7 and D8 (both test ok) Then we have Q9 BC184 and Q19 BC214 (both test ok in circuit) The 220uf Q31 that is connected to the
U13 L7905 input pin 2, I have removed it and test 100% ok, so the problem, in my opinion, could be the TLC555??
I have been thinking about removing it but I haven't got a replacement and I wanted to check everything else before doing that as it is double soldered on the PCB and not easy to remove.
I will order a new TLC555 just in case.



On 24/09/2022 21:04, Anatloy Dirtymad wrote:
both TLC555? then both are CMOS, not NE555.