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Author Topic: [Fixed] Enterprise 64 Video issue (Read 4282 times)

Offline slugman

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[Fixed] Enterprise 64 Video issue
« on: 2015.July.07. 18:17:48 »
Hello,

I'm the Lucky owner of a enterprise 64 that I found on a flea market in France. The person who sold me said me that he got him from his company (Christmas gift) , he never used it and left it in the box. The machine is in mint condition and all the documentations/cables were properly stored in the box. So I think that he really never used it.

I powered it and unfortunately I have video issue. Colors seems ok but it's like if there is a sync problem. I've put a vidéo HERE to show you the issue.

I'll be happy if I can repair it :) When I was young I had an Amstrad CPC 6128 and I just discovered this Enterprise machine and really want to look more of his capabilities

If anyone has experienced such issue , I'll appreciate any help in order to fix it.

Thanks,
Fabien
« Last Edit: 2015.July.10. 11:54:19 by slugman »

Online Zozosoft

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Re: Enterprise 64 Video issue
« Reply #1 on: 2015.July.07. 19:10:28 »
Now I'm can't view the video (I'm on vacation, only with 0G internet on mobile phone). But the most common problem, the no 12V for video circuits. It is make a running screen (with colors). Tr2 transistor (BC337) dead by the dried out C9 capacitor. Replace both.

Offline slugman

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Re: Enterprise 64 Video issue
« Reply #2 on: 2015.July.07. 20:49:04 »
Thanks zozosoft for the information, yes symptoms are a running screen with colors.

I started to open it. But I cannot fully remove the cover.



Sound like there is still something blocking around the video port. but I've removed all visible screws.


Or maybe there is still a screw hidden behind the white serial sticker ? If someone can confirm, I prefer not damaging the sticker if there is nothing behind. Thanks
« Last Edit: 2015.July.07. 20:56:55 by slugman »

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Re: Enterprise 64 Video issue
« Reply #3 on: 2015.July.07. 20:57:11 »
Yes, it is one screw under the label, at the corner near to the monitor conector (see on my page the Inventory, you can see many serial label photos). With sharp knife you can carefully blend up the label corner.

Online gflorez

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Re: Enterprise 64 Video issue
« Reply #4 on: 2015.July.07. 20:58:28 »
Take care with the keyboard strips!

Offline slugman

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Re: Enterprise 64 Video issue
« Reply #5 on: 2015.July.07. 21:38:32 »
I've opened it. took some pictures of the motherboard and removed TR2 (BC337) and C9 (100uf, 10v). Will go to an electronic shop to buy replacement components.

Thanks for your help, I really appreciate!












« Last Edit: 2015.July.09. 12:41:47 by slugman »

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Re: Enterprise 64 Video issue
« Reply #6 on: 2015.July.09. 10:32:27 »
Little note: your board is a ISSUE 4, see the company name on them, it is FLAN! (Rare)

The problem with this type Philips capacitors are common.

Online gflorez

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Re: Enterprise 64 Video issue
« Reply #7 on: 2015.July.09. 11:31:07 »
Its strange. If I click the thumbnails it waits forever but doesn't shows the images.

If I take the links to another Firefox window they load.

Online BruceTanner

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Re: Enterprise 64 Video issue
« Reply #8 on: 2015.July.09. 11:52:57 »
Its strange. If I click the thumbnails it waits forever but doesn't shows the images.

If I take the links to another Firefox window they load.

It is very strange because I get the same using Chrome! :shock:

Online Zozosoft

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Re: Enterprise 64 Video issue
« Reply #9 on: 2015.July.09. 12:11:32 »
Same for me. I think some incompatibility with the forum software and the image hosting server.

Slugman! If you don't mind then I'm can move your photos to the forum server.

Offline slugman

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Re: Enterprise 64 Video issue
« Reply #10 on: 2015.July.09. 12:43:37 »
Same for me. I think some incompatibility with the forum software and the image hosting server.

Slugman! If you don't mind then I'm can move your photos to the forum server.

I've attached the photos to my last post. Will be easier to view.

Offline slugman

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Re: Enterprise 64 Video issue
« Reply #11 on: 2015.July.10. 11:53:01 »
Video issue fixed! :ds_icon_cheesygrin:

Thanks a million zozosoft!

No will see to add an expansion memory card and a SD card interface (saw the posts in the forum) hope it's still possible to order them.
« Last Edit: 2015.July.10. 12:17:15 by slugman »

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Re: [Fixed] Enterprise 64 Video issue
« Reply #12 on: 2015.July.10. 12:01:56 »
Great news! :smt038

Online gflorez

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Re: [Fixed] Enterprise 64 Video issue
« Reply #13 on: 2019.March.13. 01:35:35 »
Sorry, this is about another EP64 with a video problem, but I don't want to create a new thread with a similar title.

The unit had an insidious side video oscillation like when there is not enough +12v on the video circuit, but the owner has tested every single component on the +5v and +12v phases near the heat sink. Four years ago he started a thread about this on the RetroWiki web page, but I still was not a member.  Recently he has resumed his interest on fixing his EP64, and he has received and followed advices from very skilled persons, but all the tips have been unsuccessful.

Then somebody proposed I must repair it personally, thinking that I had a knowledge about Enterprises.... I have accepted, promising to put my best on resolving the issue, but with not a lot of confidence on my skills, only on my stubborn...  

Today the PCB arrived. I spent some minutes on connecting the board, show the video issue, then study the components.

At last I did my first check with the multimeter, on the two 7805 regulators on the heat-sink. When switched ON the PCB, one of the regulators had +4,89v at the output pin, but the other only +4,10v. "Can it be this?" I replaced the "faulty" 7805 with a new one. Now the values where similar on the two regulators. I plugged the video cable, and then the image was rock solid.

Stunned, I have just fixed an Enterprise almost by random...

23022-0

I have plugged it a new membrane and my EXDOS+HxC unit to test thoroughly the unit, and a DIR worked good on WP.
« Last Edit: 2019.March.13. 01:48:32 by gflorez »

Online Zozosoft

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Re: [Fixed] Enterprise 64 Video issue
« Reply #14 on: 2019.March.13. 14:19:15 »
At last I did my first check with the multimeter, on the two 7805 regulators on the heat-sink. When switched ON the PCB, one of the regulators had +4,89v at the output pin, but the other only +4,10v.
I think one 7805 are completly dead, and power come through the cross diodes (D2/D3). I already see same problem.

The big question: "the owner has tested every single component on the +5v and +12v phases near the heat sink."
How it is tested previously? :oops:

Quote
Stunned, I have just fixed an Enterprise almost by random...
Nice work! :smt038