OK, so I have an early (B01xxx) 7854 with at least one bad MOSTEK chip. My scope has the separate ROM board with four MOSTEK chips, the FPLA and two 2716's.
I have read the posts here, and on Tekscopes2, but am not clear on what the fix is. The ROM images I have located seem to be either newer, or cannot just be burned into the MCM68766 EPROM. I can burn these, and read the MOSTEK chips. And have repaired Fluke and HP instruments with bad ROM in this way.
Does any one have the ROM images, read directly from the MOSTEK chips? The p/n's are:
160-0408-00, 160-0409-00, 160-0410-00, 160-0411-00
Or, does anyone know other step are required to use the available images? I have read about pulling the FPGA and jumpering, in conjunction with some other ROM?
Any help appreciated!

You need to split them in two if you are talking about the Pentti Hakka versions.

Here's some ROM images that friend of mine took which may work for you

HtH
Dave

________________________________

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of testtech@...
Sent: 27 March 2014 18:14
To: TekScopes@...
Subject: [TekScopes] 7854 ROM, again ..




OK, so I have an early (B01xxx) 7854 with at least one bad MOSTEK chip. My scope has the separate ROM board with four MOSTEK chips, the FPLA and two 2716's.
I have read the posts here, and on Tekscopes2, but am not clear on what the fix is. The ROM images I have located seem to be either newer, or cannot just be burned into the MCM68766 EPROM. I can burn these, and read the MOSTEK chips. And have repaired Fluke and HP instruments with bad ROM in this way.
Does any one have the ROM images, read directly from the MOSTEK chips? The p/n's are:
160-0408-00, 160-0409-00, 160-0410-00, 160-0411-00
Or, does anyone know other step are required to use the available images? I have read about pulling the FPGA and jumpering, in conjunction with some other ROM?
Any help appreciated!

Actually I *think* that is one of the patch ROMs, in which case that is possible - is it binary zeros or all FFx?

Regards,
David Partridge


________________________________

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Bob Koller
Sent: 27 March 2014 19:46
To: TekScopes@...
Subject: Re: [TekScopes] 7854 ROM, again ..




Thanks David! I appreciate it. One of the images, U210 is bad, there is no data...





On Thursday, March 27, 2014 11:52 AM, David C. Partridge <david.partridge@...> wrote:


You need to split them in two if you are talking about the Pentti Hakka versions.

Here's some ROM images that friend of mine took which may work for you

HtH
Dave

________________________________

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of testtech@...
Sent: 27 March 2014 18:14
To: TekScopes@...
Subject: [TekScopes] 7854 ROM, again ..

OK, so I have an early (B01xxx) 7854 with at least one bad MOSTEK chip. My scope has the separate ROM board with four MOSTEK chips, the FPLA and two 2716's.
I have read the posts here, and on Tekscopes2, but am not clear on what the fix is. The ROM images I have located seem to be either newer, or cannot just be burned into the MCM68766 EPROM. I can burn these, and read the MOSTEK chips. And have repaired Fluke and HP instruments with bad ROM in this way.
Does any one have the ROM images, read directly from the MOSTEK chips? The p/n's are:
160-0408-00, 160-0409-00, 160-0410-00, 160-0411-00
Or, does anyone know other step are required to use the available images? I have read about pulling the FPGA and jumpering, in conjunction with some other ROM?
Any help appreciated!

Follow up - I looked at the image here, it isn't blank - have you tried another EPROM?

Regards,
David Partridge


________________________________

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Bob Koller
Sent: 27 March 2014 19:46
To: TekScopes@...
Subject: Re: [TekScopes] 7854 ROM, again ..




Thanks David! I appreciate it. One of the images, U210 is bad, there is no data...

The ROM is bad then as the image for U210 I sent is NOT all FF

Regards,
David Partridge


________________________________

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Bob Koller
Sent: 28 March 2014 16:23
To: TekScopes@...
Subject: Re: [TekScopes] 7854 ROM, again ..





I burned U210 and the 2716 PROMS's, but it still reports a ROM failure during POST. I wonder if the FPGA might also be bad? My programmer does not have a profile for the 82S107.





On Friday, March 28, 2014 8:15 AM, Bob Koller <testtech@...> wrote:


Yes, it is all FFFF

I'm coming in late on this conversation but I have repaired these for the vintageTEK museum.  The patch ROMs must match the main ROMs and the FPLA.  The best thing to do is to replace the four Mostek ROMs with two 27128s programmed with the .PAT images.  Then you have to reprogram and replace the 2716s so they match with the same version.  Then you must remove the FPLA as that code is embedded in the .PAT images.  Then you need a 24 pin to 28 pin adapter for the 27128 and you have to rewire the CS as you have combined two ROMs into one EPROM.  I put information on my personal web site at http://modularsynthesis.com/elec_repairs/repairs.htm.  It is towards the end of the page.

I do not see the attached images ?


Regards, Dana.

I've put them here:

<https://groups.yahoo.com/neo/groups/TekScopes/files/7854/>

Dave

RE:

The 7854 and ROM issue. I have no more time or interest in this instrument. I installed the Penti ROM set and wiring per Dave, and it will now get past the ROM failure, apparently, and stall on the RTC test failure, and not get past that.
So, before I put this non-functional 7854 up on Ebay, probably parted out, I am offering it complete with the waverform calculator to the Group. S/N is B010126, no plugins, very little apparent use, the CRT HV lead has virtually no black dust accumulated on it. A little surface dirt from years of storage though. Comes with the Penti ROM installed and the original MOSTEK set as well. Looking for $150 + shipping. PM for a shipping quote.

Hello,
          
Could You give me an idea of shipping to Seattle, WA?
specifically
the 98115 area code.

Thank You,
Mark

RE:

The 7854 and ROM issue. I have no more time or

interest in this

instrument. I installed the Penti ROM set and

wiring per Dave, and it will

now get past the ROM failure,

apparently, and stall on the RTC test

failure, and not get past

that.

So, before I put this non-functional 7854 up on Ebay,

probably parted out,

I am offering it complete with the

waverform calculator to the Group. S/N

is B010126, no plugins,

very little apparent use, the CRT HV lead has

virtually no

black dust accumulated on it. A little surface dirt from

years

of storage though. Comes with the Penti ROM installed and the

original MOSTEK set as well. Looking for $150 + shipping. PM for a

shipping quote.

[Non-text portions of this

message have been removed]

[Non-text portions of this message have been removed]

Sorry, that was supposed to be a PM....

Mark

Hello,

Could You give me an idea of shipping to Seattle, WA?

specifically

the 98115 area code.

Thank

You,

Mark

RE:

The 7854 and ROM issue. I have no more time or

interest in this

instrument. I installed the

Penti ROM set and

wiring per Dave, and it will

now get past the ROM failure,

apparently, and stall on the RTC

test

failure, and not get past

that.

So, before I put this non-functional 7854 up on Ebay,

probably parted out,

I am offering it complete with

the

waverform calculator to the Group. S/N

is

B010126, no plugins,

very little apparent use, the CRT HV lead

has

virtually no

black dust accumulated on it. A

little surface dirt from

years

of storage

though. Comes with the Penti ROM installed and the

original MOSTEK set as well. Looking for $150 + shipping. PM for a

shipping quote.

[Non-text

portions of this

message have been removed]

[Non-text portions

of this message have been removed]