Title: RED Digits
Post by: WD8BXS on 03. August 2022, 15:54:53
Got a repair in, and I keep getting intermittent red digits.
Ver 6 latest firmware .
Any advice an where to start?
I have already gone over all the IQ solder joints.
TNX DE Chuck |
Title: Re:RED Digits
Post by: DF8OE on 04. August 2022, 06:35:07
Hi Chuck,
this cannot be related to IQ soldering.
As you know, "red digits" are meaning that UHSDR got no "success" message from local oscillator chip (via I2C). Why not looking at the I2C connections, the power supply of the oscillator or the oscillator itself ::)?
Good luck!
vy 73
Andreas |
Title: Re:RED Digits
Post by: WD8BXS on 04. August 2022, 12:46:54
Hello Andreas,
I am so sorry, I DID mean the I2C connections...
I have soldered at oscillator and through the complete chain. to the MCU
Today I will attempt to see where the chain is broken when the digits go red.
TNX Chuck |
Title: Re:RED Digits
Post by: DF8OE on 04. August 2022, 15:24:05
There are many possible reasons, but they all point to "bad I2C communication to LO Chip". It can be a bad connection, a wrong soldered pullup on I2C lines, a capacitor at these lines (some PCBs have pads for such a capacitor - never publish it), noisy power supplies of LO and/or STM32 or bad STM32 / LO chip.
Also try reducing I2C speed in configuration menu (if it is cranked up to the "red region")
vy 73
Andreas |
Title: Re:RED Digits
Post by: WD8BXS on 05. August 2022, 23:38:05
Hooked up a known good UI Board, still red digits!
Replaced the oscillator, still red digits!
Not much left to check!!!
Seems like I always get the tough ones, hihi
de Chuck |
Title: Re:RED Digits
Post by: DF8OE on 06. August 2022, 04:36:54
Have you checked correct placement of pullup resistors on SDA and SCL near to LO chip? I have seen some boards where there are soldered 90° wrong...
vy 73
Andreas |
Title: Re:RED Digits
Post by: WD8BXS on 06. August 2022, 14:15:18
Yes Andreas,
That is all good.
This is an intermittent issue, when it is working it will work for hours.
Seems to happen when you go to change bands.
de Chuck |
Title: Re:RED Digits
Post by: DF8OE on 06. August 2022, 15:23:40
Try to reduce I2C-speeds in configuration menu. May be they are cranked up.
vy 73
Andreas |
Title: Re:RED Digits
Post by: WD8BXS on 06. August 2022, 21:10:58
Thanks Andreas,
Yes I have tried that as well.
de Chuck |
Title: Re:RED Digits
Post by: DB2OJ on 07. August 2022, 07:08:20
Hello,
I've had the same problem twice.
Both times I resoldered the solder joints of the SI751
and it worked perfectly again.
73 Manfed
DB2OJ |
Title: Re:RED Digits
Post by: WD8BXS on 07. August 2022, 22:05:50
Hello Manfed,
Yes, I re-soldered it twice and also replaced it with a different one.
Got me scratching my head here, hihihi
De Chuck
WD8BXS |
Title: Re:RED Digits
Post by: DF8OE on 08. August 2022, 04:41:57
It must be an issue on the RF board. You tested it with a known-good UI and the issue stays. Temperature sensor is on the same bus. It can be the cause, too.
vy 73
Andreas |
Title: Re:RED Digits
Post by: WD8BXS on 08. August 2022, 23:40:11
| Yes, I changed the temp sensor as well |
Title: Re:RED Digits
Post by: WD8BXS on 09. August 2022, 22:32:41
Well, I think this is progress!!!
When I remove R18, the red digits go away!!
I tried replacing U11, but no luck.
Just if R18 is out...
de Chuck |
Title: Re:RED Digits
Post by: WD8BXS on 10. August 2022, 17:41:16
The Plot thickens....
If I remove R22 and R23 the issue goes away.
If I remove R51 and R52, then replace R22 and R23 the issue returns!
What do you think about that??
de Chuck |
Title: Re:RED Digits
Post by: DF8OE on 11. August 2022, 06:07:32
This has not logical explanation. I think it is only a workaround - there is a bug buried somewhere which you have not identified yet.
vy 73
Andreas |
Title: Re:RED Digits
Post by: WD8BXS on 11. August 2022, 12:13:18
Yes, I agree it is very strange!
Sadly there are no new parts to be had....
I think, just for fun, I will re-load the bootloader and firmware maybe there is a bit out of place hihi.
de Chuck, 73 |
Title: Re:RED Digits
Post by: WD8BXS on 15. August 2022, 11:40:49
Here is another interesting fact..
As long as you don't change bands, the radio will play all day .
Only when you change bands will the red digits show up!!
73 de Chuck |
Title: Re:RED Digits
Post by: DF8OE on 16. August 2022, 13:45:49
Changing bands is a wide step - thats the only difference. This cannot be buried in firmware - we would have tons of issue reports if this would be...
I think it is a hardware problem on your rf board.
vy 73
Andreas |
Title: Re:RED Digits
Post by: WD8BXS on 18. August 2022, 00:29:02
I agree, I just don't know where else to look!!!
de Chuck |
Diskussions- und Newsboard des DARC-Ortsverbandes I40 | Powered by YaBB SE
© 2001-2003, YaBB SE Dev Team. All Rights Reserved.
|