[ The P1A15 Troubleshooting Thread ] No READY. P1A15 error. Condenser charge timeout.

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i found the headers. The link says "amazon.co.uk/" but when i mouse over or click it gets changed to "amazon.com/"; had to manual type it in.

The pins on the hybrid are larger than normally seen and measure 0.8mm square; those headers look a little bit too small to me. They look like the 0.64mm square header pins commonly used on circuit boards.
 
For sure you could replace the larger stand-off pins with the header pins and put header sockets on the board.

ps. i don't know what they use for the clearcoat on the board; it is a rigid coating like an epoxy rather than the flexible coating used in the OBC, which is easily removed with a spudger.
 
It will easily chip off with a light scrap, i use the tip of an Exacto blade along the edges to break the surface, then use a wooden toothpick, finger nail, or sharp tip of a meter probe to pry the coating off.
 
More parts arrived

Replace tc4s58f, no difference

I have a tl4941 to fit, I can see pin 1 on the new one but which is pin one on the board? Is it to the corner if the board or down beside the lower of the transformer?

Thanks again
 
I looked back on the posts and found pin one and now have replaced the optical coupler…… the output voltage is now 0.1v higher than the input regardless of temperature!!!!!!!


So I will fit it back in and take some pictures…..

Watch this space
 
boothegermanshepherd said:
...

I have a tl4941 to fit, I can see pin 1 on the new one but which is pin one on the board? Is it to the corner if the board or down beside the lower of the transformer?
pin 1 of the TL494 connects to the 12V return and is down toward the Output pin 3 of the hybrid board
 
These are the bits I have replaced

https://imgur.com/a/gL9wAv7


Where do I go next?

Are there any resistors and capacitors that you can identify for me and I replace...... I am determined even though I have another inverter coming tomorrow!
 
Did you replace the large capacitor in the corner that holds up the 12V via to ground? looks like 0.8 to 1.0 uF would work there. That would be my first choice for items to replace.

Does the "12V" supply seem to hold up or drop when heat is applied, either to the cap or anywhere else on the board? is the 12V stable or does it get affected when the circuit is misbehaving.

Also the same question for the +/-5V supplies--they should be nearly equal value, but are they different when it misbehaves? Are they equal when it's working okay? How do they respond when the circuit board gets localized heating and cooling?

Use cold spray to "freeze" different parts to see if it "heals" and gets to working correctly. Then use localized heating to cause it to fail or degrade.

What i'm trying to get at is this:
Firstly, the power supplies needs to be rung out to determine whether they are an issue or the cause. An oscilloscope may be necessary because this is a switching power supply with ac signals; be careful with the ground leads to not short or cross the signal to the wrong return, i.e. VL and 12V return are not the same, don't short them thru the scope, don't know what might happen.

After the ps is given a clean bill of health, then ring out the signal from beginning to end to find where to problem starts.
 
perfect and I really do appreciate your time

the large capacitor, do you know what package it is because its fairly large

will a small one do of the same value

with the 12v supply its just a regulated supply which I have not monitored, but I will check now

Back to basics


EDIT

found it



measured big cap at bottom corner while on the board: 753nF at 1kHz with smart tweezers. i would guess this would be a 1uF cap.
 
By power supplies, i'm talking about the supplies on the board, not the external device. Only interested in what is happening on the board.

the big cap imperial size is 0805 footprint.
 
There is a huge difference between the + and - low voltage supply, +5.18 vs -5.80. They should be nearly equal value with opposite polarity.

Would you be able to measure the pin voltages over on the TL494 with respect to the 12V return. That chip is what creates the switching of the power transformer to make the + and - 5 supplies.

The tiny blue resistor on pin 6 is 10k, and the capacitor on pin 5 is reading 1nF. These two set the base frequency for the PWM. Freq(osc) ~ 1.1/Rt x Ct, so the internal oscillator is about 110kHz.

Pin 14 is supposed to be a 5V reference generated internally. i see that it is connected 13 which sets the output control. With pin 13 at 5V, the output frequency is 1/2 of the oscillator, so i would expect that the PWM frequency is around 55kHz.

The little black resistor measured 10k, and the cap between pins 2 and 4 measured 100nF.
 
Morning Kenny

Done the checks as per your last message and all has added up, I just have not replaced any of the components that you have specified with readings, is this the next step?
 
Lic said:
I still have my bad MCU around, so If I can help some how let me know.
Howdy Lic,
Thanks for the offer, we could try to repair your hybrid board if you would like to help. Simple test and measurements on the bench once the hybrid is removed.
 
boothegermanshepherd said:
Morning Kenny

Done the checks as per your last message and all has added up, I just have not replaced any of the components that you have specified with readings, is this the next step?

Did you post the pin voltages? Did you measure the passive component values to compare? i was getting different readings on the little black resistor depending upon using a meter vs smart tweezers, 10k vs 3k , so not absolutely sure. Not sure if it matters as that is just a pull-down to ground of pin 4 which sets the duty cycle.

When you had the ic removed did you notice any traces or vias that were under the chip?

There are 2 FETs inside the device which are used in a push-pull arrangement. If one of those were degraded then the switching of the power transformer may not be symmetric. Would need a scope to measure this.
 
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