# Unidentified digital indicator chip

#### Rcleaver

Joined Nov 22, 2019
12
Hi. This is a my first posting and I am hoping that the collective wisdom of the site will assist me with a little problem.

Some background; I bought a small lathe a couple of years ago. This has a variable speed drive with a digital speed indicator. The lathe was bought from Warco in the U.K. but was manufactured in China. The speed controller was manufactured by KB Electronics in the U.S.

The problem is that recently the speed indicator started to flicker and has now died. In all other respects, the lathe is working fine and there is nothing wrong with the speed control itself. Now, I traced the problem back to a failed 5V voltage regulator on the power supply board and I replaced the component so that I now have 5V at the display driver chip.

I then decided to replace this IC but I have no idea what it is, who made it and whether there is an available replacement. My search of catalogues revealed nothing so I am completely in the dark. It is 20-pin and bears the lettering 1511TGCCA and CCF608.00E1117 on the underside. I wonder if it is of Chinese origin. The four-digit display has the letters 5641BH-S on the side.

Some photos attached illustrate the issue.

If any of you could shed any light on this, I would be immensely grateful.

Regards

Richard

Joined Jul 18, 2013
19,438
The four digit display is a common 4 digit seven segment display device.
The 20pin IC is most likely a micro processor and would have proprietary code.
How is the RPM detected? IOW, what type of sensor?
Max.

#### Rcleaver

Joined Nov 22, 2019
12
The four digit display is a common 4 digit seven segment display device.
The 20pin IC is most likely a micro processor and would have proprietary code.
How is the RPM detected? IOW, what type of sensor?
Max.
Thanks for your reply. There is a slotted disc on the headstock shaft that runs between legs of a U-shaped sensor with a cable connection to the board with the display on it. I can send a photo if it would help. I don't think that this is the problem as the indicator should show zero when the lathe is stationary but it has no LED segments alight which makes me think it's either an IC failure or an indicator failure.
Regards

#### Rcleaver

Joined Nov 22, 2019
12
I am assuming that after you fixed the voltage regulator, the display was still dead. Right? Do you have any way to look at the signals at the 4-pin connector? It might be easier to get a whole new module like this:
Arduino 4 pin
https://www.lelong.com.my/arduino-iot-4-digit-7-segment-display-module-tm1637-driver-littlecraft-192744589-2020-05-Sale-P.htm
Thanks for your reply. You are correct that having managed to get 5V to the IC, the display is still dead. I am wondering if a fault in the IC caused over current in the 5V line and blew the regulator.
I don't have any way of looking at the signal from the transmitter on the headstock shaft.
I like the idea of the Arduino module. I know nothing about Arduino devices so that is something I'll need to research.
Regards

#### jpanhalt

Joined Jan 18, 2008
8,335
That U-shaped thing is an interrupter. It provides a stream of pulses to the MCU or display MCU that counts them and converts that to RPM (e.g., if it produces 10 pulses per revolution, 500 pulses per minute would be 50 rpm).

Like Max, I suspect it is very standard. KB might sell the part ($$) or find a substitute. It is probably the chip's numbers are specific for the manufacturer (i.e., proprietary), so even if you could find the identical chip, if it is programmable, you would need to program it. A short cut would be to find something to do the same job. If you have any way to look at the signal on those pins -- friend with oscilloscope, local high school, ??? --knowing what you are dealing with would be a great help. Does your multimeter have a frequency function? You could attach ground lead to any ground, then probe the pins with the lathe turned on.. Thread Starter #### Rcleaver Joined Nov 22, 2019 12 That U-shaped thing is an interrupter. It provides a stream of pulses to the MCU or display MCU that counts them and converts that to RPM (e.g., if it produces 10 pulses per revolution, 500 pulses per minute would be 50 rpm). Like Max, I suspect it is very standard. KB might sell the part ($$$) or find a substitute. It is probably the chip's numbers are specific for the manufacturer (i.e., proprietary), so even if you could find the identical chip, if it is programmable, you would need to program it. A short cut would be to find something to do the same job. If you have any way to look at the signal on those pins -- friend with oscilloscope, local high school, ??? --knowing what you are dealing with would be a great help. Does your multimeter have a frequency function? You could attach ground lead to any ground, then probe the pins with the lathe turned on.. Unfortunately, it's a relatively simple meter without a frequency function. I don't have access to a 'scope although I could hire one if necessary. I think that the reality may be that I have to forget about the display and rely on the sound and 'feel' of the lathe to judge the speed. Just like the old days, in fact! #### jpanhalt Joined Jan 18, 2008 8,335 If your meter has a voltage (DC) scale, set it to 5 volts (or more) and probe with the lathe off. One pin should be ground, one either 5V or 3.3V. Then with the lather on, another pin may start showing a voltage that increases a little with speed. That would be a signal pin. If both pins that are not ground or supply show voltage, then it may be a serial digital signal, such as SPI. I have small lathe that I modified with a DC motor and KB control. No RPM. I just go by sound and feel while cutting. With a larger lathe that may not be as practical. #### MaxHeadRoom Joined Jul 18, 2013 19,438 Like Max, I suspect it is very standard. KB might sell the part ($) or find a substitute
I suspect the tach is not KB related, just an add on and separate item. KB drives do not have tach features.
The fact the display is dead sounds like a supply problem.?
Max.

Joined Jul 18, 2013
19,438
There is these ebay (372539617338) for $10.00 appears to be programmable as to number of input pulses. Max. Thread Starter #### Rcleaver Joined Nov 22, 2019 12 If your meter has a voltage (DC) scale, set it to 5 volts (or more) and probe with the lathe off. One pin should be ground, one either 5V or 3.3V. Then with the lather on, another pin may start showing a voltage that increases a little with speed. That would be a signal pin. If both pins that are not ground or supply show voltage, then it may be a serial digital signal, such as SPI. I have small lathe that I modified with a DC motor and KB control. No RPM. I just go by sound and feel while cutting. With a larger lathe that may not be as practical. Thanks for that. I'll give it a try. It's a small lathe (500W motor). Thread Starter #### Rcleaver Joined Nov 22, 2019 12 There is these ebay (372539617338) for$10.00 appears to be programmable as to number of input pulses.
Max.
The supply to the board is fine now that I have replaced the blown 5V voltage regulator. It could be the display or the IC circuit driving it. I agree that the tach board is an add-on item and probably not from KB so I shall ask Warco if a replacement is available through the original manufacturer. I'll check out that e-bay reference. Many thanks.

#### TeeKay6

Joined Apr 20, 2019
528
Hi. This is a my first posting and I am hoping that the collective wisdom of the site will assist me with a little problem.

Some background; I bought a small lathe a couple of years ago. This has a variable speed drive with a digital speed indicator. The lathe was bought from Warco in the U.K. but was manufactured in China. The speed controller was manufactured by KB Electronics in the U.S.

The problem is that recently the speed indicator started to flicker and has now died. In all other respects, the lathe is working fine and there is nothing wrong with the speed control itself. Now, I traced the problem back to a failed 5V voltage regulator on the power supply board and I replaced the component so that I now have 5V at the display driver chip.

I then decided to replace this IC but I have no idea what it is, who made it and whether there is an available replacement. My search of catalogues revealed nothing so I am completely in the dark. It is 20-pin and bears the lettering 1511TGCCA and CCF608.00E1117 on the underside. I wonder if it is of Chinese origin. The four-digit display has the letters 5641BH-S on the side.

Some photos attached illustrate the issue.

If any of you could shed any light on this, I would be immensely grateful.
View attachment 192171View attachment 192172View attachment 192173

Regards

Richard
Normally an IC's part number is printed on the top, not bottom, of the part. Your photos show the bottom; can you see any markings on the top?

#### Rcleaver

Joined Nov 22, 2019
12
Normally an IC's part number is printed on the top, not bottom, of the part. Your photos show the bottom; can you see any markings on the top?
Hi TeeKay, thanks for replying. There is nothing on the top of the IC and no sign of abrasion. Like you, I was expecting some identifier on the top of the chip (from my experience in electronics 40 years ago) which just adds to the mystery.

#### LesJones

Joined Jan 8, 2017
2,417
How did the 5 volt regulator fail ? Was it giving an output of less than 5 volts or more than 5 volts ? If it was outputting more than 5 volts it could have caused components on the tachometer board to fail.

Les.

#### Rcleaver

Joined Nov 22, 2019
12
How did the 5 volt regulator fail ? Was it giving an output of less than 5 volts or more than 5 volts ? If it was outputting more than 5 volts it could have caused components on the tachometer board to fail.

Les.
Les,
That's a very good question! My guess is that the regulator was subjected to more than its rated max current (100mA). This could have happened if there was a short in the IC or another component on the board. I noticed that the display was flickering for quite a while (i.e. days) before finally going out. I wonder if this on/off switching killed the regulator
Richard.

.

#### LesJones

Joined Jan 8, 2017
2,417
From your answer can I assume that you did not measure the output voltage of the regulator before replacing it ?

Les.

#### Rcleaver

Joined Nov 22, 2019
12
From your answer can I assume that you did not measure the output voltage of the regulator before replacing it ?

Les.
On the contrary; I started at the +5V pin on the tacho board which read 0V then went back to the power supply where I found the transformer and rectifier giving a good 13V dc. The output of the regulator was giving 0V so I changed it and that provided me with 5V at the tacho board. Clearly, something caused the regulator to fail but I'm not sure what. I surmise that whatever has failed on the tacho board caused the regulator to blow.
Richard

#### Dodgydave

Joined Jun 22, 2012
8,587