Commodore 1084S-D2 - Another repair

[demonlg]

Hello,

i'm again with another commodore monitor, this time is a 1084S-D2 (Daewoo chassis)

This monitor is of my friends, it have buyed on line but during shipping it damaged! Opened monitor i have found a crack con the PCB bottom of flyback! My friends turned on the monitor when arrived but it don't power up, no led, no sound nothing, dead!
I don't know if the monitor working before shipping, my friends says yes but i'm not sure, then i have glued the 3 pieces of pcb, checked all component between crack and then i have soldered all pcb wires cracked, i have opted to se little wires for little pcb lines, and for ground i have soldered between crack with a wire to enforce.

Now the monitor powers up, led ok, but no raster, the tube glow up, if i connect my C64 i have only sound, contrast and brightness ti middle but nothing no raster.

I don't find chematics for D2 but for D1, it's seems the same without TTL switch on rear side.

Throubleshoting guide says " IF NO RASTER CHECK IC201 TDA2595 12v input, REPLACE TDA2595, CHECK 15v OUTPUT on FLYBACK.

Tomorrow i will check all power lines, but any idea from here?

Thanks

Emanuel

 

[Hugo Holden]

Likely, if your friend said it was working before shipping, it was.

Therefore, most likely the reason it is not working now, is that it was violently decelerated during shipping. Or kicked off the back of a truck is the usual M/O for unloading parcels these days. Or have a look at this video and you will see what happens with a typical parcel delivery:

There was enough force to fracture pcb tracks, as the flyback tried to ram through the surface of the pcb, or tear its way off. This suggests that the unit was dropped from a significant height and decelerated very abruptly on a hard surface, in other words, not enough soft packing too, the more the soft packing the lower the deceleration when something is dropped. It will always be dropped, at least once or twice in the shipping process.

You have already repaired most of the cracks, there will likely be some damage elsewhere that you have not found yet, sometimes cracked tracks can be very hard to spot without a lot of light and magnification.

So I would suggest, keep inspecting and searching for more damage.

 

[robert_sissco]

Or have a look at this video and you will see what happens with a typical parcel delivery:

This is so far from the truth. The delivery people have never asked me how I was doing, let alone even knock on my door, I had to fight FedEx to actually ring my buzzer when I lived in an apartment.

Joking aside, yea, it is kind of sad, but part of it is also the packing. I ordered two C64's "For parts or repairs" since I wanted any good chips off of them (VIC-ii, SID, CIA, ect) and more importantly, the case since I was doing a Pi64 conversion. These cases were cracked (CRACKED, not shattered but had easily repairable cracks in them) and the seller simply wrapped them in a single layer of bubble wrap and put them in a box twice the size needed with no filler, so they shook around in transit. Got them, and one case was literally shattered on the userport corner, both top and bottom of the lid (these were both breadbins) and some how 5 keys snapped off the keyboard, 2 on the shattered one and 3 on the other one. Thankfully I have replaced enough key stocks I bought some in bulk a while back so replacing them was easy, and the springs were in the box (loose) since they broke in the box during shipping.

On the otherhand, when I ordered my SX-64 from eBay, the seller packaged it so well that if a nuclear bomb went off, and as long as the truck was not disingrated in the blast, the Vault Dweller could have used it when they found it.

The issue for the parts or repair was both had bad PLA's and both had a working VIC-ii, but one gave up the ghost almost right away. It also had a damaged RF modulator, which I am sure was done in shipping as well since that was in the shattered case). That was also the board I did some threads on about repairing (user port edge connector missing the ground pin, memory not always reporting the full amount, keyboard faulty when was due to cracked traces under the CIA chip. Ultimately everything got moved to a board I bought from DIY Chris and works great now, still pisses me off since I think so much of that board was due to the seller shipping it so crappy. And I paid $50 for shipping on the two. I sold a for parts Amiga 500 (It was given to me to try and repair but beyond my scope, but was a fully populated board) and I shipped it for $70, and with the cost of packing material the the cost to ship it was closer to $90, but I took that hit because I said I would ship for $70 and even if it was a shattered case, I was going to make my damnest effort to make sure it got to the buyer in the same condition I showed on eBay.

 

[demonlg]

My friend have sended to me a photo of the monitor working after shipping.

I suspect to the ABL pin on FLYBACK is lost or component in this zone of circuit. I check it this night. This line is starting from TDA 3507 pin 19 and is trought to one 1n4148 and a resistor after the pin 15 (or 11) of the flyback.

Emanuel

 

[Hugo Holden]

This is so far from the truth. The delivery people have never asked me how I was doing, let alone even knock on my door, I had to fight FedEx to actually ring my buzzer when I lived in an apartment.

Joking aside, yea, it is kind of sad, but part of it is also the packing.

Yes, as I mentioned, it is possible to pack things in a manner that will allow all types of shipping abuse.

It reminds me of a story; many years ago my daughter's class at school were tasked with a design of packing that would allow you to throw a chicken egg off the top of a one story building and have it not turn into Humpty Dumpty (break).

I gave her a hand with the project (as parents often do). We came up with the simple idea of putting the egg in a plastic Jam jar filled with water. It survived the test and didn't break, though the method is not suitable for VDU's.

 

[robert_sissco]

It reminds me of a story; many years ago my daughter's class at school were tasked with a design of packing that would allow you to throw a chicken egg off the top of a one story building and have it not turn into Humpty Dumpty (break).

I gave her a hand with the project (as parents often do). We came up with the simple idea of putting the egg in a plastic Jam jar filled with water. It survived the test and didn't break, though the method is not suitable for VDU's.

I had something like that in school as well. I froze the egg in a block of ice by suspending it from a tupperwear lid with string so it was right in the middle. The ice cracked but the egg, because it was also frozen, stayed whole. I can't remember what I got on that since I don't recall the teacher saying we can't freeze is solid, but yea, that is not a good method for packing VDU's either

 

[demonlg]

I have checked the ABL circuit but it's ok. Now i have to check all voltage lines output from flyback, seems not starting the vertical scanning and conseguent not have the raster, but heater on the tube is ok.

I don't know...probably a wires resoldered in wrong position, any of wire are going to front panel regulators, contrast and brightness!

Emanuel

 

[demonlg]

Repaired, a little crack on a 24v rail from EAT and a solder pont on 15 volt rail diode in output of EAT.