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Andrew96_

Epoch repairing

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Now time is going by epoch resources are getting thin on the ground, so thought I would start a repair thread.

 

Recently turned up a small pile of boards from ebay for £10, In the pack was a epoch mk1 lamp board. Now i find Mk1  boards better than the later MK2 one stop boards because although the mk2 are supposed to be better,  modified versions I have found the fet transistors that do blow have not been up-rated at all and STILL blow! also the mk2 drive the alpha display from a small surfacemount custom chip and if you are unlucky to unplug the alpha or plug it on with the power connected it tends to blow the alpha drive output of this chip! the Mk1 board the alpha is driven from a much more robust PIC chip which does withstand this. how do I know...... yes have done it!!

 

so what happens to the MK1 boards is the lamp transistors burn up! and this MK1 board was no different! I presume a bulb holder in the machine gets shorted out somehow which burns up the transistor driving it

 

the board!

 

post-7246-0-04179900-1520523316_thumb.jpg

 

no dispute here on the blown transistor!

 

post-7246-0-00603100-1520523327_thumb.jpg

 

all others tested with a meter and no other shorts found so a bit of hot air from a chip re-work station and chip was out! It had taken the pad off where it had burnt so soldered on a replacement wire!

 

post-7246-0-03705000-1520523358_thumb.jpg

 

New transistor chip fitted and the wire neatly soldered to the leg of the chip, metered to make sure it is connected as it should be

 

post-7246-0-16126200-1520523371_thumb.jpg

 

and so job is done and the board will live to fight another day instead of being scrap!

 

post-7246-0-05922700-1520523400_thumb.jpg

 

Edited by ghost of andrew96
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It sure is a pain when those SMD tracks come off. Rivets are no good obviously as there's no through hole.

Did you ever try getting some proper PCB adhesive and sticking a new bit of pad on? Superglue just doesn't have the temperature rating which is a  shame.

 

Nice work.

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It sure is a pain when those SMD tracks come off. Rivets are no good obviously as there's no through hole.

Did you ever try getting some proper PCB adhesive and sticking a new bit of pad on? Superglue just doesn't have the temperature rating which is a  shame.

 

Nice work.

 

naa I never bothered as it was expensive and as can be seen a bit of wire does the trick! there are still 7 pads to hold the smd transistor on and that's good enough for me!

 

sticking copper on with superglue is not good! fumes the superglue gives off when soldering to copper on top of it gives off some nastys! that's why I use kynar wire then go over it with solder resist which seals it to the board like glue!

 

cheers bob

Edited by ghost of andrew96

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This was a faulty lamp transistor on the reel board I did some time ago, but this one was just short and not blown a hole in it, so pads were all intact! removal is not that difficult really and quite quick! I had already removed U1 as that was short too!

 

 

 

Edited by ghost of andrew96

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Now time is going by epoch resources are getting thin on the ground, so thought I would start a repair thread.

 

Recently turned up a small pile of boards from ebay for £10, In the pack was a epoch mk1 lamp board. Now i find Mk1  boards better than the later MK2 one stop boards because although the mk2 are supposed to be better,  modified versions I have found the fet transistors that do blow have not been up-rated at all and STILL blow! also the mk2 drive the alpha display from a small surfacemount custom chip and if you are unlucky to unplug the alpha or plug it on with the power connected it tends to blow the alpha drive output of this chip! the Mk1 board the alpha is driven from a much more robust PIC chip which does withstand this. how do I know...... yes have done it!!

 

so what happens to the MK1 boards is the lamp transistors burn up! and this MK1 board was no different! I presume a bulb holder in the machine gets shorted out somehow which burns up the transistor driving it

 

the board!

 

attachicon.gifIMG_1803.JPG

 

no dispute here on the blown transistor!

 

attachicon.gifIMG_1804.JPG

 

all others tested with a meter and no other shorts found so a bit of hot air from a chip re-work station and chip was out! It had taken the pad off where it had burnt so soldered on a replacement wire!

 

attachicon.gifIMG_1806.JPG

 

New transistor chip fitted and the wire neatly soldered to the leg of the chip, metered to make sure it is connected as it should be

 

attachicon.gifIMG_1807.JPG

 

and so job is done and the board will live to fight another day instead of being scrap!

 

attachicon.gifIMG_1808.JPG

You may become suddenly popular, on these forums!!

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You may become suddenly popular, on these forums!!

 

Most know I no longer do repairs for others and have not done so since 2015, or sell any replacement boards. It is not worth the hassles. I do these things now for my own enjoyment and sometimes document it and hopefully it will help others.

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For those of you that “think” the mk2 one stop lamp boards are somehow better than the original... think again... yes they updated transistors but the ones that STILL fail are the SAME small soic 8 pin devices as used in the original mk1 boards!!

 

they go short circuit just the same!!!!
 

9647D988-22F8-48B0-8393-AE1296F1E172.thumb.jpeg.0b3a0b5439e4b7199a950c99f661c491.jpeg

 

In fact I think personally the mk2 lamp boards are worse than the mk1 as removing and plugging in the alpha while switched on will blow the custom actel chip!!!! This won’t happen on mk1 boards as the PIC chip that drives the alpha is much more robust!!!

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I have changed now from using hot air as it can tend to melt the plastic sockets nearby!!! I now use hot tweezers which the tips cover all the legs

013F7714-C2A4-45B9-8822-7E7151AD4119.thumb.jpeg.2aede80431aac5f726b1b176f0a7a85b.jpeg

 

there was 2 transistors short ( causing a few very bright lights) but with the tweezers and a cleanup they are not difficult to replace as long as your careful as the print can easily be dislodged or pulled off very easily!

6333F0FE-8577-41C1-B623-426AE0D3AB85.thumb.jpeg.55009c2f70d521425ed3ec536162a0c9.jpeg

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This 4 reel board was intermittent on one phase to the stepper motor on reel 1 so would error with 2.1 error sometimes! Pressing on the reel board would restore the phase, carefully inspection under the microscope revealed pin 4 on U13 had become dry jointed and detached from its pad! Fluxing and reflowing cured it! All pins were reflowed as none looked that good under the microscope!!!

 

F29EC9FC-9A8D-4124-9CF6-6B5E5CD5E614.thumb.jpeg.58f3fb7390989f92093c3d6307b55ef2.jpeg

Edited by Andrew96_
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Mk1 lamp board, fault lamps bright! U1 lamp drive transistor was short, replaced and  lamps were all the right brightness but loads stuck on!! A careful sweep of the board and U12 (74HC4094)  had 2 small holes in the top!! So it has now been removed!!

 

8EBCF8B2-87F5-4652-AFF4-431CDC80B069.thumb.jpeg.c9773810a21f87402c3b2add54534516.jpeg

 

EAD8090C-5D51-4F1F-9206-A4D308C7312A.thumb.jpeg.53df3c1987ef73a7dafe75d4a5172fd3.jpeg

Edited by Andrew96_

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So.... did it cure it!!! Nope!! Still lamps on! Section on still was from  U11

removed another 74hc4094 and yep bad!!

E78C6C84-5A70-4576-82DD-C1C82DE76485.thumb.jpeg.5f3aa61261ae8222c5e27b2b8239a70b.jpeg

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STILL lamps on!!! But at least fewer now!!

 

U25 next...... and yep another 74hc4094 bad!!

1FB01BD6-8859-4812-87A8-79A9C8C308E1.thumb.jpeg.39c3ad61c29222f58835633b9488242d.jpeg

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Now it’s better! But no 7 segments working, so there are only 2 more 74hc4094 on the board U10 and U31. So removed and yep all high outputs!! So replaced!! That was my last 74hc4049 chips used so glad there was no more on the board! Well that cured it!! I guess because they are cmos chips they got spiked out somehow, possibly The board plugged in / or out with the power on, seems something must have happened to take out every one as that is extremely unlikely for them to all fail at exactly the same time otherwise!! Lol

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These the ones I sent you a good while back? If so I’m Glad your making good use of them, saves them from the bin :) 

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14 minutes ago, -Crest- said:

These the ones I sent you a good while back? If so I’m Glad your making good use of them, saves them from the bin :) 

yes they are! finally got to looking at them!

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This little bugger reel board gave me the right runaround!!!

 

780D3A3B-515D-4CD7-B5CA-DAC8A3B5FF8B.thumb.jpeg.51f3ef616d5332b9fb8cb4e3f2400210.jpeg

 

this would give a meter error 6.0 which is rather strange when it doesn’t even control the meters!!! The meters are done from the next board after this in the chain. So my first thought was it must be stopping communication to the next board so went for the 8A470 as I thought a good place to start, it wasn’t that! So for want of pushing forwards I started removing and checking the chips in my tester one by one!!

 

U6,  U5, U7, U8, U9, U10,  this took some time! Then tested U14 74hc165 and the tester said FAIL !!! Bingo!! Changed that and it booted up perfectly and initialised perfectly!!

that took some time!! Fault fixed!!!

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Fantastic, thanks for posting that's a great read! I've been trying to understand more about the serial link comms for ages. It's great to see what's driving it. I'm glad you're working on Epoch again lol.

This is where people struggle so much with Epoch. A Gen meter 6.0, so they change the Meter, then the main board, then the Psu... then the hopper board if they get that far... but actually it's the Reel driver board/bad comms  causing it...It's great to see you working on Epoch again. Hopefully people will have a go and see its actually a good tech.😎

 

Edited by MattyL
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On 9/14/2020 at 11:10 PM, Andrew96_ said:

This little bugger reel board gave me the right runaround!!!

 

780D3A3B-515D-4CD7-B5CA-DAC8A3B5FF8B.thumb.jpeg.51f3ef616d5332b9fb8cb4e3f2400210.jpeg

 

this would give a meter error 6.0 which is rather strange when it doesn’t even control the meters!!! The meters are done from the next board after this in the chain. So my first thought was it must be stopping communication to the next board so went for the 8A470 as I thought a good place to start, it wasn’t that! So for want of pushing forwards I started removing and checking the chips in my tester one by one!!

 

U6,  U5, U7, U8, U9, U10,  this took some time! Then tested U14 74hc165 and the tester said FAIL !!! Bingo!! Changed that and it booted up perfectly and initialised perfectly!!

that took some time!! Fault fixed!!!

Yup I thought this one was odd to, 6.0 error lol

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On 9/14/2020 at 11:46 PM, Generation said:

I have a couple of faukty lamp boards you can have if helps you out in any way?

@Andrew96_

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