2 Falcon issues: with new PSU it needs reset to boot / can’t clear all solder to install NVRAM

[satjanand]

Hi forum,

My Falcon had a dodgy PSU that had one of the 5V and one of the 0V cut from the motherboard plug. It worked, but I couldn’t get external SCSI Zip drive working. So I ordered a PSU from Exxos some time ago, and a clock patch and RTC+socket from Centuriontech. The clock patch was installed, the socket to accomodate the RTC not yet. Today I replaced the PSU with the one from Exxos, and my Falcon behaved differently: turning it on send a black 313p video signal, but the Falcon doesn’t do much. Until I hit reset: then video turns into the right signal and the Falcon works as expected.

My first question is: why did this happen?

My second question:

I was given the advice to replace the NVRAM, so I started deslodering it. But there are three solderpoints that wont come off, each one in a corner pin: 1, 13, 24 (12 was succesfully removed). The Dalas chip is out, so they do get kind of liquid. But no matter what I try, they stay in there holes.

I have used a weller soldering iron, with suction tool, and with copper braids. I have tried an 868D hot air station up to 355 degrees Celcius, also no avail. I have also used a ZD-915 deslodering machine, but it also won’t take out these last three solderpoints. I have used flux and new solder to renew the old solder that may have just dried over the years. But not matter what I try, I can’t get these three to clear.

They’re all corner points and I wonder if different solder has been used here. I need some advice as to clear these three solder points (or how to install the low profile NVRAM socket), I really don’t want to kill my Falcon here.

[exxos]

The PSU problem is bad caps in the reset circuit, it is in the PSU FAQ https://www.exxosforum.co.uk/forum/viewt ... 245#p26117 and Mandatory fixes pages.

I can't talk for centurion tech items. I doubt his clock patch uses latest fixes which I designed some time ago. You may want to ask him for support about his stuff.