Help with tracing a pedal.

[dmnCrawler]

I am trying to trace the KMA - Tyler The Freq Splitter. I am having trouble figuring out how to determine the SMD capacitor values. There are no markings on the caps and if I am correct they can not be measured in place. I am unsure of the values of C1, C4, C5, C14, C15. I am guessing on the input diode value [1N4148]. And I am very unsure of the schematic. I have spent several days going over it and think I have all the traces correct, but I have only been building for 4 months and my knowledge is limited.

Also the low and high pass jacks do hook up to the wrong filters. I believe they are miss labeled on the PCB. I will fix them in the final version of the schematic. Any help, hints ,tips or other resources to use are greatly appreciated.

If this is the wrong place please let me know the right place.

C1	x			R1	220-1​	22R	TH	D1	x
C2	47​	16V		R2	2204​	2.2M		D2	5mm LED	White Clear
C3	220​	16V		R3	1002​	10k		D3	3mm LED	Yellow Clear
C4	x			R4	2203​	220k		D4	3mm LED	Yellow Clear
C5	x			R5	2203​	220k
C6	10​	16V		R6	3902​	39k		TRIM	105​
C7	10​	16V		R7	1002​	10k		TRIM	105​
C8	47​	16V		R8	1001​	1k		TRIM	105​
C9	x			R9	1001​	1k
C10	10​	16V		R10	2201​	2.2k		Low Pass	A100K	Dual
C11	10​	16V		R11	3300​	330R		Level	A100K
C12	10​	16V		R12	1002​	10k		Mix	B10K
C13	10​	16V		R13	1004​	1M		High Pass	A100K	Dual
C14	x			R14	2203​	220k
C15	x			R15	1002​	10k		+ -	SPDT	ON-ON
C16	10​	16V		R16	2204​	2.2M
C17	10​	16V		R17	2204​	2.2M		Wood	3PDT
C18	10​	16V		R18	1002​	10k		Bypass	3PDT
				R19	1002​	10k		Steel	3PDT
IC1	7660SCPAZ			R20​	1002​	10k
IC2	TL074C			R21	1003​	100k		IN	Stereo Switching
IC3	TL072C			R22	1001​	1K		OUT	Stereo Switching
IC4	TL074C			R23	1001​	1K		LP Send	Stereo Switching
				R24	1001​	1K		LP Return	Stereo Switching
Enclosure	1590XX			R25	1002​	10k		HP Send	Stereo Switching
				R26	1004​	1M		HP Return	Stereo Switching
				R27	1001​	1K
				R28	1004​	1M

 

[Robert]

Unfortunately you really need to remove them to get an accurate measurement.

Be careful, if any of them are SMD film capacitors they will melt when you try to desolder them. Those have to be isolated in-circuit by removing other components around them, then you can measure them while still installed on the PCB.

 

[dmnCrawler]

Unfortunately you really need to remove them to get an accurate measurement.

Be careful, if any of them are SMD film capacitors they will melt when you try to desolder them. Those have to be isolated in-circuit by removing other components around them, then you can measure them while still installed on the PCB.

I had a feeling it would not be easy. And I believe it is only the film caps that I need measurements for. I am hoping that someone may have some ideas of ranges just from the circuit design and where the caps are placed.

 

[Devoureddeth]

Unfortunately you really need to remove them to get an accurate measurement.

Be careful, if any of them are SMD film capacitors they will melt when you try to desolder them. Those have to be isolated in-circuit by removing other components around them, then you can measure them while still installed on the PCB.

Have you ever tried the SMD multimeter tweezers? I have tried the cheaper versions and it is only useful for resistors.

 

[Robert]

Have you ever tried the SMD multimeter tweezers? I have tried the cheaper versions and it is only useful for resistors.

Wow, I missed this... Better late than never though, right?

I have since picked up another Pace station with MT-200 tweezers. It has significantly cut down the amount of time to takes to measure SMD components. Unfortunately it vaporizes film caps just as quickly as a regular iron, but it makes it much easier to isolate them in the circuit.

It gets enough use that I bought a second station just for the tweezers so I can go back and forth with the iron quickly.