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Post by serafis on May 8, 2022 21:19:13 GMT -5
When I jump jump legs 1 (vout) and 3 (vss) of ic164 with a 100 ohm resistor, it immediately resets. The mains relay clicks off, the LED goes to yellow and then after around 8-10 seconds the main relay clicks back on and the LED goes green. This is the same behaviour as when I power it off and on again from the main switch, i.e no display and none of the remote or front panel buttons do anything.
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Post by mastertech on May 8, 2022 21:39:19 GMT -5
Ok, good. Everything that is going on, even with the USB thumb drive is telling me that ic162 is functioning properly. But it appears as though ic151 is not functioning at all. So we can start poking there.
One thing first. Did you try formatting the thumb drive in NTFS?
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Post by serafis on May 8, 2022 21:45:52 GMT -5
Yes, I've tried it in FAT, FAT32 and NTFS.
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Post by mastertech on May 8, 2022 21:47:49 GMT -5
Ok, get me the voltage reading on these pins of ic151.
82, 83, 84 and 1
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Post by serafis on May 8, 2022 21:53:52 GMT -5
Pins 1, 83 and 84 all read 3.270V. Pin 82 fluctuates between around 2.75 and 2.95V on the DMM, in a regular cycle of around 1-2 seconds. I can put the 'scope across if it that would help.
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Post by serafis on May 8, 2022 21:59:13 GMT -5
The range of pin 82 may be wider (e.g. even 0-2.95V over a faster time)- my DMM updates fairly slowly.
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Post by mastertech on May 8, 2022 22:04:32 GMT -5
Well I would like to see if your scope can read if there is any activity on these pins during a reset (unplug and plug back in). Do a reset for each pin while holding probe on pin before plugging back in. I also would like you to see if your scope can read the 2 crystals on ic151 for correct frequency function.
I have to go for tonight so I will check your results tomorrow.
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Post by serafis on May 8, 2022 22:05:32 GMT -5
Quick look on the 'scope - Pin 82 has a square wave pulse that rises from around 800mV to around 3.16V for around 150mS, then falls back to 800mV for around 50mS. I can measure it more accurately if required.
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Post by mastertech on May 8, 2022 22:11:50 GMT -5
No need to remeasure. That seems odd. Check the other 3 pins and let me add pins 61 and 30 to this test.
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Post by serafis on May 8, 2022 22:45:33 GMT -5
Ok, pick it up tomorrow, sleep well, and thanks.
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Post by serafis on May 8, 2022 23:53:32 GMT -5
Some of these pins behave differently if a USB stick is plugged in. Pin 1 gets 2.8V constant when first turned on, goes up to around 3.3V constant when the main relay clicks. Same behaviour with USB plugged in. Pin 82 gets around 3.1V constant when first turned on, stays constant after mains relay clicks. But with USB plugged in, starts at 3.1V constant, then goes into the cycle described above (scope screenshot attached) just after the main relay clicks. Pins 83 and 84 get around 3.3V constant when first turned on, remains at that level when the main relay clicks. Same behaviour when USB plugged in. Pjn 61 gets just under 3.3V V when first turned on, goes up around 10mV and stays constant at around 3.3V after mains relay clicks. Same behaviour when USB plugged in, although perhaps a tad under 3.3V. Pin 30 starts at 0V, stays there even after mains relay clicks. But with USB plugged in, it starts at around 3.3V and drops to zero when the USB LED stops flashing. Scope screenshots of the Pin 82 cycle when USB plugged in:   |
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Post by mastertech on May 9, 2022 8:57:08 GMT -5
Can you get a reading on those crystals?
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Post by serafis on May 9, 2022 16:30:24 GMT -5
Yes, took a while as it's hard to find a place/way to read accurately, but they both seem to be performing ok at 10MHz and 32.768MHz respectively. The 10MHz reading was taken across the legs of the crystal. Measuring across the legs of the 32.768KHz crystal yielded an unstable waveform which was different, but still unstable on reversing the probes. Measuring between one of the legs and Gnd gave a stable waveform as per the second image below.   |
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Post by serafis on May 9, 2022 16:32:25 GMT -5
I also noticed that IC154 was getting fairly hot - still touchable but hotter than anything else around it.
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Post by mastertech on May 9, 2022 19:27:55 GMT -5
I have a lot of assumptions going on in my head. All your test so far are meaningful. Try removing the eeprom (ic152) and scope ic151, pins 83 and 84 again, restarting unit both times while scoping.
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