Hi!
Can you post high quality pictures of before and after?
These are too small.

When you have Varta disasters you have to understand that it could steal hours on hours to repair it.

Attached are the highest resolution pictures I have. I realize there is still a lot of corrosion present in its current state, but I'm trying to balance removing the corrosion vs risking further damage while trying to remove it. A lot of the corrosion and damage seems to be on the RTC portion of the circuit, like the crystal and a least one of the ICs I replaced, but I'm assuming that the board should still boot without the RTC. Is that a correct assessment?

dylanfm wrote on 2026-04-15, 23:10:

Attached are the highest resolution pictures I have. I realize there is still a lot of corrosion present in its current state, but I'm trying to balance removing the corrosion vs risking further damage while trying to remove it. A lot of the corrosion and damage seems to be on the RTC portion of the circuit, like the crystal and a least one of the ICs I replaced, but I'm assuming that the board should still boot without the RTC. Is that a correct assessment?

RTC is required.
I had a similar situation and I had to go down to a lot of continuity test on traces.
It probably works but it's going to be a long project considering all the probing.

Traces will need to be repaired.

No quick solution IMO. That was a nice Varta bomb.

Based on the damage, I would get fairly aggressive with a repair. This includes removing the mask on any damaged traces to expose the bare copper underneath. I would also remove any components and solder points with corrosion on them. Assuming the components are salvageable, those can be resoldered. The thing with corrosion like this is that a lot of damage can be hiding underneath.

I have a board that was heavily corroded like this. While I could get it initially booted, it was highly unstable. Exposing the traces lead to finding a lot of corroded traces, a number of which needed to be repaired.

It is a fair bit of work to do. But it's also a good exercise in board repair.

Yep everything Shponglefan said. This needs removal of one row of chips 7404 7404 7414 7407, Q2 transistor, clock gen can, row of resistors diodes and inductor, small 32K resonator and resistor next to it
then wash all the green stuff with detergent and toothbrush
then scrape all the solder mask not eaten by corrosion yet - battery alkaline has wicked under the solder mask (it can also wick into the chip packages!) and will keep corroding if not aggressively removed
then use tiny drill to clean VIAs
then find all the places where tracks were broken and patch them up, you can start by tinning all the tracks to speed things up
then plug all VIAs with thin wire and solder on both ends
then nail polish to protect from oxidation
then you either clean all the parts removed earlier or replace with spares new/pulled from scrap boards

lot of not very difficult work

Nexxen wrote on 2026-04-16, 07:55:

RTC is required. I had a similar situation and I had to go down to a lot of continuity test on traces. It probably works but it' […]
Show full quote

RTC is required.
I had a similar situation and I had to go down to a lot of continuity test on traces.
It probably works but it's going to be a long project considering all the probing.

Traces will need to be repaired.

No quick solution IMO. That was a nice Varta bomb.

Is the RTC required even to POST, issue beep codes, and/or come out of reset? What about the battery?

rasz_pl wrote on 2026-04-17, 00:31:

Yep everything Shponglefan said. This needs removal of one row of chips 7404 7404 7414 7407, Q2 transistor, clock gen can, row o […]
Show full quote

Yep everything Shponglefan said. This needs removal of one row of chips 7404 7404 7414 7407, Q2 transistor, clock gen can, row of resistors diodes and inductor, small 32K resonator and resistor next to it
then wash all the green stuff with detergent and toothbrush
then scrape all the solder mask not eaten by corrosion yet - battery alkaline has wicked under the solder mask (it can also wick into the chip packages!) and will keep corroding if not aggressively removed
then use tiny drill to clean VIAs
then find all the places where tracks were broken and patch them up, you can start by tinning all the tracks to speed things up
then plug all VIAs with thin wire and solder on both ends
then nail polish to protect from oxidation
then you either clean all the parts removed earlier or replace with spares new/pulled from scrap boards

lot of not very difficult work

I have now replaced the chips, 32khz crystal, the resistor next to it and if few others. I don't have a replacement for the oscillator. I think I made a mistake by soldering sockets to replace the components when I did. I think I'm going to need to unsolder them and several other components so that I can properly trace through the circuit and scrape off the solder mask like you say. If I had a schematic, I think I could fix this, but without that, I'm really not sure. I feel like I'm going to need to try to draw the schematic for this portion of the circuit before I am comfortable unsoldering everything all at once.

dylanfm wrote on 2026-04-17, 05:38:

Nexxen wrote on 2026-04-16, 07:55:

RTC is required. I had a similar situation and I had to go down to a lot of continuity test on traces. It probably works but it' […]
Show full quote

RTC is required.
I had a similar situation and I had to go down to a lot of continuity test on traces.
It probably works but it's going to be a long project considering all the probing.

Traces will need to be repaired.

No quick solution IMO. That was a nice Varta bomb.

Is the RTC required even to POST, issue beep codes, and/or come out of reset? What about the battery?

To my knowledge yes. No RTC no movement.

Look for Necroware on youtube, he repaired lots of boards and by watching you can learn tons.
It was my starting point for many repairs.