Flyback transformers - options for replacements

[Surfheart]

Hi I have a 512K that has a slight display jitter when the floppy drive is accessed and after being on for about an hour will start a nearly inaudible high pitched whine.

According to Larry Pina, these symptoms are of a failing flyback transformer.

What options do I have for seeking replacements for this?  I assume that they cannot be purchased as new parts?  I am worried if the only option is to transplant them from other machines that ultimately they will all fail.

Any advice?

 

[uniserver]

http://www.ebay.com/itm/157-0026B-Flyback-1570026B-Replaces-Apple-HR-42031-/400566688902?pt=LH_DefaultDomain_0&hash=item5d43a29c86

make sure to change all the big electrolytics. , and AC filter cap too.

and your issues should be solved, maybe refresh the joints as stated in DMS.

 

[360alaska]

Yep, Ive been stocking up on these, once they're gone, they're gone...

 

[Elfen]

maybe refresh the joints as stated in DMS.

When you refresh the solder joints, do not just heat them. Desolder the joint and remove as much of the solder as possible and then resolder with fresh solder for a clean joint. Just reheating the joint will cause the solder to muck up and start cracking.

 

[uniserver]

well as stated in DMS, it says to use vacuum desoldering.

 

[Surfheart]

Thanks very much for the link and advice guys!

 

[miniMOJOman]

which models do that part work for?

 

[uniserver]

all.

 

[miniMOJOman]

aye, well thats good to know thanks!!

 

[uniserver]

well i should specify what i mean by all.

128k 512k Plus.

Will also work in the SE and SE/30,   The Classic and Classic II have a different flyback.

 

[miniMOJOman]

AH! Even better!

"Will also work in the SE and SE/30"  does that mean that it isn't the exact part but can be fitted to work in these models? 

 

[uniserver]

Yes it will work.

Also the cracked joints on the A/B sometimes the connections get really bad, especially when people keep hitting their compact with the soul of a shoe and keep running it.

The Joints not only crack but they carbon up and fry as well.

So not only use vacuum desoldering, but scrub the pin with wick and flux to clean it. Before Soldering it back up with 

fresh 60/40.

You could also desolder the whole header, and use a dremel (stone or wire wheel) if you want to be extra thorough. 

 

[uniserver]

looks like ARTMIX sells one as well.

but shipping is much more.

http://www.ebay.com/itm/Mac-128K-512K-Plus-SE-SE-30-Flyback-Transformer-New-Condition-/301556148137?pt=LH_DefaultDomain_0&hash=item463625a7a9

 

[miniMOJOman]

 yeah and it *looks* like artmix has only 1...?

 

[uniserver]

Also check out this other thread:

https://68kmla.org/forums/index.php?/topic/21632-macintosh-plus-boot-problem-maybe-a-cracked-solder/page-4

Posted 01 February 2015 - 09:44 AM


this guy was a good source,  but it looks like he is sold out.

http://www.ebay.com/itm/291117849340

i ended up buying quite a few from him.

here are some more on ebay that look to cross-reference out.

http://www.ebay.com/...=item1c3183a3fd

( this one being the least expensive )

http://www.ebay.com/...=item5d43a29c86

here is one that ARTMIX sells.

http://www.ebay.com/...=item46335abfda

here is one more:

http://www.ebay.com/...=item1c3183979f

Some good part numbers to search for:

157-0026B - USED ALOT IN THE 128 / 512K /PLUS

157-0026C

157-0026V

157-0042A

157-0042B

157-0042C - USED ALOT IN THE SE/30 BACKWARDS COMPATIBLE

HR 42031

HR 40343

Really for someone doing a hillbilly 128/512k/plus A/B fix, Find you a Mac SE A/B they should be plentiful and they already have the upgraded flyback and the Upgraded Q3 and CR5, you can re-use… because the SE has a fan almost all the time these parts are in great shape on the SE, there is always that exception, you will especially notice the size of CR5, well CR2 on the SE AB, is like double the size.

lol like this here

buy it now $ 7.99 and you get pretty much all that you would need.

http://www.ebay.com/...=item20f5202335

 

[Surfheart]

I just thought, will it matter that I have a 240V (Australian) analogue board, it shouldn't matter for the flyback?

 

[uniserver]

Yup the flyback is the same.

 

[miniMOJOman]

I'm wondering how much the Apple Techstep Diagnostic tool can help with these problems.. I got a techstep not too long ago, but havent had time to really play with it..Uni, do you happen to know if it can help diagnosis a/b problems?? I know it can analyze power supply voltages but.... 

 

[uniserver]

Really to be honest when an A/B comes in.. I don't even diagnose it.

I just get right on into it...  Clean, Do the caps, suck out all the cracked joints, then test.    and from there, it either works fine or it does not,  if not, from this point i can make a good estimate as to what its going to still need to work properly as far as time/costs.

As i said in this thread:

https://68kmla.org/forums/index.php?/topic/21632-macintosh-plus-boot-problem-maybe-a-cracked-solder/page-4

the main parts that go bad are the Regulator / Diode / Flyback / AC Filters / C1