SE/30 Horizontal strip NOT analog board related...

[solidpro]

Hi

I have an SE and an SE/30 and I'm using both complete units to switch components to try and home in on a few different problems.

SE has large black and white rectangle checkerboard.
SE/30 has a single, bright horizontal line on the CRT.

SE/30- I'm thinking, reflow all the solder on the analog board - particularly around P1 - no improvement. So I recapped the whole board - nada. So I replaced TDA1170N - no change. Same stripe.

I switch in the (checkerboard) SE board and I get a full screen checker. If I switch the SE/30 mainboard over into the SE, I get the same horizontal stripe.

So, the horizontal stripe issue follows the SE/30 mainboard between both cases/CRTs/analogs. I recapped the whole mainboard - no change (I do hear a chime upon startup). I don't get it. The only thing I'm moving is the mainboard (no cables).

I tried fiddling with the 2 x variable resistor things and nothing changes. But then again the SE/30 issue follows the board over to the SE case/analog board, which displays a full-screen checker with the SE mainboard..

Just to complicate things - if I put the checkerboard SE mainboard into the SE/30 case I have the SAME ANALOG horizontal stripe.

So it feels like 2 things are causing this horizontal stripe - one which follows the SE/30 mainboard and the other which remains with the SE/30 analog/CRT.

Does anyone have any other ideas?

Thanks

 

[Johnnya101]

Hold on, first you say you put an SE board in the SE/30 (bad) case and it works (with checkerboard), then you say you put an SE board into the SE/30 (bad) case again, and it has a line? So does it checkerboard at all or no?

 

[solidpro]

SE in SE case = checkerboard
SE/30 in SE/30 case = horizontal line.
SE into SE/30 case = horizontal line.
SE/30 into SE case = horizontal line.

Doing more searching I've re-flowed UE8 on the mainboard - no change.

 

[Johnnya101]

Oh, okay, that's clears it up.

Here's a link with a similar/the same issue, with some helpful leads. Going by this, it's probably likely a bad solder joint on the AB, and some bad traces by the video circuit on the LB.

SE/30 - Horizontal line on Startup

Hi All, I have a Mac SE/30 that I picked up. Started up fine a few times but after about a week it started up with a blank screen and a bright horizontal line. Also not boot noise on power up. So, based on lots of advice I have recapped BOTH the analog board and the motherboard. Now when i...

68kmla.org

When you resoldered, did you use good quality NEW solder?

 

[chillin]

Lifted from
https://www.jagshouse.com/classicrepair.html

6. A Bright Horizontal Line in the Black Monitor​

Symptoms
(1) The SE/30 starts up and works normaly. After a while, the monitor suddenly blacks out only with a bright horizontal line.
OR
(2) When turning on the SE/30, you can hear the startup bong but see only a bright hrizontal line in the black monitor.

Diagnosis
The vertical sweep circuit on the analog board doesn't work.
The major cause of this trouble is either of (1) connection failure due to ageing and/or cracks in the soldering of the P1 connector, or (2) troubles of the vertical sweep IC chip at reference U2 (12-pin TV, TDA1170A) on the analog board.

Solutions
(1) The first thing to do is to check the P1 connector. If the problem is caused by connection/soldering failure of the P1 connector, you will see the burnt and/or charred P1 connector. Desolder, clean and resolder the P1 connector.
(2) If the problem still persists and the culprit is the U2 IC chip, replace it with a new TDA1170N chip.

When the U2 IC chip is broken, you may see another symptoms such as:
(1) The screen is shrunken to the upper/lower half of the monitor and the opposite half blacks out,
(2) The upper/lower half of the screen is extended in the vertical direction.

7. Checker Flag Pattern​

Symptoms
When turning on the power, you don't hear startup bong. The monitor displays the checker flag pattern.

Diagnosis
(1) The most probable cause is connection troubles between the ROM-SIMM and the ROM-SIMM slot.
(2) Another cause is inappropriate installation of RAM-SIMMs. The memory size of RAM-SIMMs in Bank A is smaller than that in Bank B. You recently upgraded the memory but the configuration was wrong.

Solutions
(1) Pull out the ROM-SIMM from the ROM-SIMM slot. Clean the ROM-SIMM and the ROM-SIMM slot with volatile cleaner or ethanol. Then connect the ROM-SIMM to the ROM-SIMM slot correctly and tightly.
(2) See "Principles of memory upgrade for the SE/30" in the next section, 8. Jail Bar Pattern or Smile Mac in Jail.
When you install SIMMs of different memory size, install the larger ones to Bank A and the smaller ones to Bank B. Each Bank requires a set of four SIMMs of the same memory amount.

​

 

[solidpro]

I've read all those articles and posts which is why I'm stumped. I've removed as much old solder as possible (I have a rework station as well as using good old copper braid) but still bad. I guess I'll just have to go over the AB all over again.

I may well try and remove UA8 altogether and resolder it back...

 

[Bolle]

Your SE/30 logicboard isn’t outputting a vertical sync signal. The vertical counter at UF8 is most probably going to be the issue. Replace it with a new one.

 

[solidpro]

I switched the UA8 with a known good IC from another SE/30 with terrible corrosion and...... no change using the 'known good' SE board.

I removed it carefully, all the pads look good, gave it a clean and re-soldered using clean new solder and no flux at all. Can't work it out....

 

[solidpro]

I just whipped off UF8, cleaned all the pads, re-attached. The horizontal line is still there, but it does look /different/.... It looks like it's showing graphics but compressed into white line.... Is UA8 and UF7 the same chip? anyone know where I can get new ones still?

 

[solidpro]

Ok it looks like UD8/UE8 are LS166A and UF8/UG8 are LS393, which I can get a few from ebay new. I'll order them and replace all 4 and see what happens. I won't get my hopes up.

Is anyone out there able to confirm that I'm correct in thinking UD8/UE8 are the same chip and that UF8/UG8 are the same chip? I realise only one pair of these are to do with verticle sync but as they're all looking corroded, I'm just going to take all 4 off and replace all of them.

Any other ideas gratefully anticipated....!

 

[joshc]

The SE/30 BOM should help you with identifying parts on the board: https://docs.google.com/spreadsheets/d/1CAzGjHxQaQrduQC-hQ8sB2I6Y56fUlCWdJMCUDho0NE/edit#gid=0

UD8 - F253
UE8 - LS166A
UF8 - LS393
UG8 - LS393

Replacing all of these is a good start, as you say they are corroded from capacitor leakage.

 

[solidpro]

Hmmm, can't seem to find a source of SN74F253 (mine are either branded TI or motorola). I can get SN74F253D - does anyone know what the D means?

**edit** looks to simply be stating it's surface mount - just what I need...

 

[obsolete]

I had a similar problem and found several threads describing the same thing, a bright horizontal line, with no resolution. I am not sure whether @solidpro ever got their SE/30 fixed, but I figured mine out, so I thought I would document it here so others can hopefully find it in the future.

It was the PALs. Probably UG6 as that's where VSYNC appears to originate, but I swapped them all out at once, so I can't confirm it was that one.

I swapped the PALs as a set of 5 between two SE/30 logic boards, and the issue (bright horizontal line) followed the PALs. So if you have this problem and it's not the analog board, it's not UF8, it's not a cracked solder joint at the connector on either end of the power & video cable, it might be the PALs. Thanks to Bolle, we can program new ATF16V8Bs that work great in place of the originals. That's what I used.