Issue 4B - I created myself the problem
Posted: Mon Jan 15, 2024 11:36 am
Hello everyone!
So here is my call for help and kindly ask if people can help me find and solve whatever problem i created.
For starters i have a very basic understanding of electronics but still trying to figure things out; then i bought the basic tools to try to help finding the problem: digital multimeter, more or less decent microscope and solder stuff.
Here is a description of how i got to this situation:
- it was working fine all stock i could load games with mobile phone and play, sometimes some would crash but seemed ok
- then i found there is a replacement for the power input converter - TSR1-2450 - that we could swap in to remove the heating and the big heatsink so i replaced it and it was working just like was before
-then i found the composite mod and i did it and all worked as before no issues
- then i found the advise to recap that seemed logic to me due to very old caps so i ordered a recap kit; here i made a mistake as i replaced all without 1 at the time and test (i think i tested after the first 2 that were the ones near the video out circuit and was ok)
- after replacing all it does not work anymore correctly.... i had very few some good boots, with color in the image and dandanator board giving ok in the tests, them random failed boots with not even sinclair text and quite random results. Then i did my best to find any solder issue or short, then i resoldered many many pins - all lower memory, ula, caps, and many more.
- then i put an lower memory ic backwards and things got worse so i ordered the lower ram board that replaces the ics
So after learning the hard way the "if ain't broke don't fix it" i now struggle with this. I have no idea why and how but every time i retouch the solder of pins i get different behavior after.
Until this morning it would boot again to the normal sinclair text, then after like 10s make some beeps and change to a white border and black screen in middle.
Then I re-soldered some more pins (i think around the high memory ics) and now i have boot to the sinclair text, then it beeps a few times and nothing else - no colors shown also.
Ah and if i boot with dandanator board it boots run those checks and then "ram fail 01234567" and no colors
Now this morning i recaped again (new caps), did my best to check for shorts or bad solders, re heated all pins in the lower/upper ram, ula, whatever else.
Now i try to start to look into power delivery to the board and i think i have issue there. But as now i have the lower ram board from retroleum i am not sure how to check the voltage on lower ram.
I have uploaded to my google drive a couple of videos and picture of my machine:
https://drive.google.com/drive/folders/ ... sp=sharing
So here is my call for help and kindly ask if people can help me find and solve whatever problem i created.
For starters i have a very basic understanding of electronics but still trying to figure things out; then i bought the basic tools to try to help finding the problem: digital multimeter, more or less decent microscope and solder stuff.
Here is a description of how i got to this situation:
- it was working fine all stock i could load games with mobile phone and play, sometimes some would crash but seemed ok
- then i found there is a replacement for the power input converter - TSR1-2450 - that we could swap in to remove the heating and the big heatsink so i replaced it and it was working just like was before
-then i found the composite mod and i did it and all worked as before no issues
- then i found the advise to recap that seemed logic to me due to very old caps so i ordered a recap kit; here i made a mistake as i replaced all without 1 at the time and test (i think i tested after the first 2 that were the ones near the video out circuit and was ok)
- after replacing all it does not work anymore correctly.... i had very few some good boots, with color in the image and dandanator board giving ok in the tests, them random failed boots with not even sinclair text and quite random results. Then i did my best to find any solder issue or short, then i resoldered many many pins - all lower memory, ula, caps, and many more.
- then i put an lower memory ic backwards and things got worse so i ordered the lower ram board that replaces the ics
So after learning the hard way the "if ain't broke don't fix it" i now struggle with this. I have no idea why and how but every time i retouch the solder of pins i get different behavior after.
Until this morning it would boot again to the normal sinclair text, then after like 10s make some beeps and change to a white border and black screen in middle.
Then I re-soldered some more pins (i think around the high memory ics) and now i have boot to the sinclair text, then it beeps a few times and nothing else - no colors shown also.
Ah and if i boot with dandanator board it boots run those checks and then "ram fail 01234567" and no colors
Now this morning i recaped again (new caps), did my best to check for shorts or bad solders, re heated all pins in the lower/upper ram, ula, whatever else.
Now i try to start to look into power delivery to the board and i think i have issue there. But as now i have the lower ram board from retroleum i am not sure how to check the voltage on lower ram.
I have uploaded to my google drive a couple of videos and picture of my machine:
https://drive.google.com/drive/folders/ ... sp=sharing