Thanks for posting this thread, Dave! :thmbsp:

I got a v1 EPROM from you a while back, and it works great. Will probably upgrade it to a v2 soon using the hex file you posted.

You're welcome, just tryin to give back a little for all the great information everybody posts here. Upgrading from V1 to V2 should be easy for you.

Dave

OMG! Dave and whoever authorized my inclusion in the Video Karma group, you are a Godsend! My poor little 621 and RA103 have been waiting a very long time for alignment. Now you have provided the final pieces needed. I previously ordered an e-prom burner (not arrived yet), and I had resigned myself to learn how to program in C. Now, thanks to you, I can invest that time and energy into what I enjoy most: restoring these old gems. Thank you. Dan

Well, I'm at my wit's end. I've tried and tried to burn my own eprom for my VA62 and have succeeded only in raising to blood pressure and loosing my hair. Would someone be merciful and sell me a modified eprom? I and my needy vintage sets would be eternally grateful!

PM sent. You might also want to look at this post:

http://videokarma.org/showthread.php?t=268392

That lets you shift newer 45.75Mhz IF sweep generators down to the lower frequencies of the older low band IFs.

Dave

Your kind offer to see me an eProm
 

Dave, please forgive my long (and possibly perceived rude) delay in responding to your post to me. I'm back in the saddle again after some health challenges. I would like to move forward with my VA62 modification and would greatly appreciate version 2 of your eProm. What is a PM? Thanks for your patience. Dan

No problem. A "PM" stands for Private Message that this forum supports. It should pop up automatically when you login to this website. On the top right of this webpage you will see the words Private Messages highlighted in blue. Left click on those words and it will take you to the private messages sent to you (just like email). I will try also try to send you a regular email.

Dave

Dave you have done a remarkable job on this mod. Thank You!!

Also want to mod the VA62a
 

Hey Dave,
Have been reading about the Eprom modification for quite some time and I am wanting to try that on my VA62a. Would you be so kind as to PM me the info? Thanks, I can't wait to work on the Sencore.

Thanks,
Denns

Mod EPROM
 

Dennis,
PM sent. I have found that you can touch up IF alignment using the VA62A, but a set that is way out of alignment usually needs a sweep generator alignment. Lately I have been using a B&K 415 along with a down converter to heterodyne its 45.75 MHz IF down to the low frequency of old TV IFs. here is a link to a post describing that:

http://videokarma.org/showthread.php...&highlight=415

Dave

An excellent modification to the Sencore.
Very commendable work developing the mod and the wright-up.
I would add some ESD (electrostatic discharge) precautions to your posts, especially for people doing the modification during dry air conditions like the winter. One of those grounded wrist straps is a good idea, as well as working on a conductive ESD matt. The screwdriver blade you show prying the EPROM out should be in contact with your finger or grounded some other way. I think some parts of this vintage are particularly prone to damage.
Another technique I use to catch the metal fragments when drilling is to use a lump of modeling clay stuck to the back of the panel. It may leave a smudge when remove, but it will catch more.

Neither File works
 

I tried both of your hex files, but neither works on the VA62. :tears:
My original Sencore VA62 EPROM 69G94-6, has the data starting at 800-FF7, while your v1 has data from 000-7FF.

All this is seen using a Minipro. All files burned to a 2732. µP for both is an Intel 8035AHL

Is there something I am missing as to why v1 doesn't work on the VA62?

Meanwhile at the same time, I am also working on an RF output dead, VA62A.
The Original VA62A EPROM 69G94-21, has its data starting at 000-9FF.
Your v1, starts at 000-7FF. Less data?

v1 works in the VA62A, however v2 does not.
v2 has data going all the way from 000 to FFF.
I didn't think that the VA62A needed the extra address line since it was a 2732.
All non functioning occurrences above, don't boot at all. Just 8888 and garbage.

Please help.

I knew I kept that UV eraser for a reason!

I just did an edit to v1 and set its start at 800 and it works!

Here for your examination, the modified file.

This is wonderful work! Thanks for providing
this very useful information allowing us to
have the functionality of the VA62 for our
older sets with the various IFs used back in
the day. If, like me, burning eproms is beyond
your pay grade I found a gentleman who
can do this: matt@mattsbasementarcade.com
I am not affiliated with him in anyway. He
Burned the chip for me and it seems fine.