Just to be sure before buying Falcon PSU

Repairs & upgrades.
Sinis
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Re: Just to be sure before buying Falcon PSU

Post by Sinis »

exxos wrote: Fri Dec 03, 2021 9:18 pm Assuming you have not wired the 5V and 12V backwards ? then you should be really up and running but some machines are just so fickle it's unbelievable. The reset circuit Generally to Blame When Fitting the New Power supply Does Not Work. But pressing the reset switch should confirm this problem assuming it is not faulty.

There is a preset trimmer on the power supply, measure the 5 V rail and very gently and slowly turn the pot (left I think) and lower the voltage to something like 4.8V and see if it helps. If the voltage starts increasing then turn the pot the opposite way.

If this does not solve the problem then it could be rather problematic to diagnose. It could be something like the clock buffer patch is not adequate in your machine but it could literally be anything.
I assume 5v and 12v are okay, as I took photos before removing cables. And there is only one +12v (the blue cable) while there is 3 red +5v cables.

Can I try to remove the Dallas RTC ? I removed it to "better" clean the motherboard while I changed the PSU ; perhaps did I made a mistake on It, or there is a problem. Falcon should start without the Dallas component ?

I'll try to mesure voltage and then lower it as you said.

Thank you for your help !
Steve
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Re: Just to be sure before buying Falcon PSU

Post by Steve »

@Sinis Your next logical step is to put the old PSU back in and check your Falcon is still working... if you do anything else you may make things worse.
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Re: Just to be sure before buying Falcon PSU

Post by exxos »

Sinis wrote: Fri Dec 03, 2021 10:08 pm Can I try to remove the Dallas RTC ? I removed it to "better" clean the motherboard while I changed the PSU ; perhaps did I made a mistake on It, or there is a problem. Falcon should start without the Dallas component ?
No do not remove the RTC.. This is very difficult to do and you may cause a lot of damage. The Falcon will not start with the RTC removed.

But when you say you removed the RTC , was it in a socket or did you un-solder it ? I am not sure what you have actually done ?

Is the floppy drive LED on the keyboard flashing at all ? On RTC faults, it will flash very fast several times then it will pause for a second and flash several times again indicating the machine is trying to start up but the RTC contents are corrupted, so it can't boot.
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Sinis
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Re: Just to be sure before buying Falcon PSU

Post by Sinis »

Steve wrote: Fri Dec 03, 2021 10:15 pm @Sinis Your next logical step is to put the old PSU back in and check your Falcon is still working... if you do anything else you may make things worse.
You're right. But the problem is that to put back the old power supply I have to unsolder the connector of the new one (see the beginning of this post: as there are no more connectors to sell, we have to take the one of the old power supply). I also have to unsolder and resolder the switch, which is less complicated, but well...

I'll do this as a last resort, but if I can avoid using the soldering iron again, I'd like to: I'm now afraid of damaging more.
Sinis
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Re: Just to be sure before buying Falcon PSU

Post by Sinis »

exxos wrote: Fri Dec 03, 2021 10:20 pm
Sinis wrote: Fri Dec 03, 2021 10:08 pm Can I try to remove the Dallas RTC ? I removed it to "better" clean the motherboard while I changed the PSU ; perhaps did I made a mistake on It, or there is a problem. Falcon should start without the Dallas component ?
No do not remove the RTC.. This is very difficult to do and you may cause a lot of damage. The Falcon will not start with the RTC removed.

But when you say you removed the RTC , was it in a socket or did you un-solder it ? I am not sure what you have actually done ?

Is the floppy drive LED on the keyboard flashing at all ? On RTC faults, it will flash very fast several times then it will pause for a second and flash several times again indicating the machine is trying to start up but the RTC contents are corrupted, so it can't boot.

Thank you and sorry for my unclear comments.

To make things easier, here is a summary:

Before the power supply operations, my Falcon was in the following state:
- I had unsoldered and removed the original NVRAM/RTC, replaced with a socket (https://www.exxosforum.co.uk/atari/store2/#0112) and a new Dallas component (https://www.ebay.fr/itm/203233472168)
- I had removed the original hard disk, replaced by the https://www.exxosforum.co.uk/atari/store2/#0036 media and a CF card
- I had replaced the original floppy drive by a new one (https://www.exxosforum.co.uk/atari/store2/#0037)
- I had removed the original RAM and replaced it with the https://www.exxosforum.co.uk/atari/store2/#0086 media and a strip https://www.exxosforum.co.uk/atari/store2/#0091
- I had added a 68882 FPU (https://www.exxosforum.co.uk/atari/store2/#0011) in the empty slot.
- I replaced the original fan with
https://www.exxosforum.co.uk/atari/store2/#0074.

At this point, before yesterday, the Falcon was almost working normally. It was booting without any problem, I had access to the partitions on the Flash card, some floppies were working but the 3 main problems I had were :
- the language and keyboard were well saved in NVRAM but not the date and time.
- almost all floppy disks (many of them original) were unreadable: worse, they weren't even great. Systematically or almost, it was the second side that was the problem. Out of about 100 floppy disks, I was able to format 2. This was what led me to replace the floppy drive with a new one, but without any improvement
- finally on some basic tests (notably the one provided on an original Falcon floppy disk), the DSP did not seem to be recognized. One of the programs sends some numbers to the DSP and waits for half of these numbers to return; the return was zero each time.
- sysinfo.exe gave this results:

IMG_7612 2.jpg
IMG_7612 2.jpg (523.86 KiB) Viewed 2143 times

For the first issue, I thought that I might have cleaned the motherboard badly (flux...) after the NVRAM operations; for the second issue, it seemed to me, from what I could see around and what was indicated to me when I submitted the problem (https://www.exxosforum.co.uk/forum/viewt ... 653#p74649) that it was relevant to replace the PSU. It was obviously a good thing to go with a new, modern power supply.

So, at this point, the Falcon was working "almost" normally.


What I did yesterday:
- I gently removed the Dallas from the stand, without difficulty (that's the whole point of the stand)
- I cleaned the whole motherboard, with care and patience, on both sides, with a cotton swab, with isopropyl alcohol (https://www.amazon.fr/gp/product/B07DWC ... UTF8&psc=1). Not only to the NVRAM, but everywhere (maybe that's my mistake?)
- I also noticed some bad traces towards the external SCSI connector (which were there originally):

IMG_7627.jpg
IMG_7627.jpg (288.87 KiB) Viewed 2143 times

I noticed that but doesn't want to do anything for the moment, as I don't plan to use SCSI things and I'm not sure it was a "problem" for the moment.
- I put back the Dallas component
- I disassembled the original power supply, unsoldered the connector and the switch, soldered the connector on the new power supply and the new power supply on the switch, and reassembled the whole.

Today:
- on startup or reset, the screen shows what you saw before (blue pixels on black screen without screen synchro)
- the diode at the bottom left lights up and stays lit
- the disk access diode stays off and never lights up, with or without flash card installed.
- the fan is running
- no beep, nothing on the keyboard

I have not yet done the manipulations to change the voltage of the new PSU. I don't dare to touch it anymore... and I'm a bit tired. I'd rather wait a bit and get back to it when I'm in good shape.

Thanks for your help... I was so happy to receive the new power supply to be able to "finalize" this Falcon (...for the anecdote, it's my birthday on monday, and symbolically, I was hoping to have a Falcon in full shape ! and be able to put the soldering iron and all the stuff in the garage, and just enjoy this beautiful Falcon)
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Re: Just to be sure before buying Falcon PSU

Post by exxos »

Thanks for the information. It sounds like your falcon may have multiple issues if the dsp isn't working and had floppy issues for starters. Floppy drive issues could be related to the dma circuit and likely bad clock patch, does your falcon have one ? Images may help.

As said before, does the keyboards floppy light flash very fast ? ( its likely to be dim and hard to see). The RTC change is difficult and often leads to falcon not booting because of track damage . its possible as the board was cleaned , the manhandling of the board weekend some tracks to the RTC you will need to look at the schematic and check all connections are good. I assume you have a battery in the RTC ? Sometimes removing it for a fee minutes and inserting again can clear corrupted RTC faults. You stated you couldn't set the RTC time in a previous post which hints to RTC issue.

How good are you at fault finding ? Do you have a scope ? Diagnostic cartridge ? For starters you would need to check the reset signal is working. But it sounds like your falcon may need a lot of diagnostics if the keyboard floppy light isn't flashing.

Edit:
I just saw you got a RTC from evilbay, I really question if it's new. But you can't remove the battery on those. But since you can't set the RTC date, and you machine doesn't boot, my best guess is RTC fault. But I think 90% of people damage tracks to the RTC when removing it, so assume that's the problem, or the RTC chip is faulty.
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Sinis
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Re: Just to be sure before buying Falcon PSU

Post by Sinis »

Hello all.

I setup the 5v to 4,8v precisely. No change.

The floppy lights quickly when I switch on the computer, no blinking at all, even with a reset button. It lights very quickly when I switch it off.

Strange things (I can’t remember if it was like that before) : even with the Falcon switched off, when I plug the monitor into the display port, the monitor has got a reaction (the screen changes).

I’m so sad.

I don’t have any tool like scope or so and I don’t know (don’t remember) how to use it.

Do you have any address to help me ? A friend gave me the name of a German guy but perhaps there is people in France who wants to repair a Falcon ? The new PSU is very very heavy and I’m scared about sending the motherboard without damage it more.

Thank you.
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Re: Just to be sure before buying Falcon PSU

Post by exxos »

The only guy in France who may help is rodolphe czuba who created the CT60. You could try him. http://powerphenix.com/
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Steve
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Re: Just to be sure before buying Falcon PSU

Post by Steve »

Sinis wrote: Fri Dec 03, 2021 10:08 pm I removed Dallas to "better" clean the motherboard while I changed the PSU ; perhaps did I made a mistake on It, or there is a problem. Falcon should start without the Dallas component ?
After reviewing your messages again this struck me.

So chain of events:
/ Falcon with original psu /
you removed old nvram & fitted a socket, then installed a new dallas rtc
*But RTC was not working properly, could not set time*


/ During PSU swap /
You removed Dallas one more time, to clean underneath the socket

If you want to do one more simple check before sending off to someone, it sounds like there is an NVRAM socket issue. It wasn't working 100% before the extra cleaning you did, then after the cleaning the entire computer stops .. I assume you used IPA also? I think you could use your multimeter to check continuety for the NVRAM pins, to see if the motherboard vias were damaged. You could also re-flow the solder. Perhaps that removing / replacing the chip cracked an 'almost' bad trace.
Sinis
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Re: Just to be sure before buying Falcon PSU

Post by Sinis »

Steve wrote: Sat Dec 04, 2021 4:01 pm After reviewing your messages again this struck me.

So chain of events:
/ Falcon with original psu /
you removed old nvram & fitted a socket, then installed a new dallas rtc
*But RTC was not working properly, could not set time*


/ During PSU swap /
You removed Dallas one more time, to clean underneath the socket

If you want to do one more simple check before sending off to someone, it sounds like there is an NVRAM socket issue. It wasn't working 100% before the extra cleaning you did, then after the cleaning the entire computer stops .. I assume you used IPA also? I think you could use your multimeter to check continuety for the NVRAM pins, to see if the motherboard vias were damaged. You could also re-flow the solder. Perhaps that removing / replacing the chip cracked an 'almost' bad trace.
Dear Steve, thank you very much for your time and your idea. That's seems logical.

I've done what I can do with tools I have : continuity is ok between socket and solder on the other side, and between solder and "other side" of each via I saw on the motherboard. What I can't test now is the Dallas component. I alose have the original component, I'll try to put it again to check.

I have another question (perhaps should I open a new dedicated post ?) : when I opened the Falcon, I saw that :

IMG_7520.JPG
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IMG_7521.JPG
IMG_7521.JPG (503.01 KiB) Viewed 2186 times
IMG_7522.JPG
IMG_7522.JPG (597.98 KiB) Viewed 2186 times
IMG_7523.JPG
IMG_7523.JPG (644.77 KiB) Viewed 2186 times

It's like that, but it's reaaaally annoying when I need to do operations on the motherboard, as it always is soldered to the cover. So, I need advices about this thing :
- what it is for ? It's probably for sound, right and left RCA pair for input, right and left for output, but is it something known ?
- should I completely remove it ? and unsoldering cables from motherboard ?
- should I keep this, and add a connector system that allow me to disconnect and connect again RCA to motherboard ?
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