All RAM chips destroyed??

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tcat
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Re: All RAM chips destroyed??

Postby tcat » Sun Apr 08, 2018 2:22 pm

Hi Martyn,

those JUx represent wire-links/zero-ohm resistors on the Iss-5 boards...They appear immediately between the ZX8302 and the right-hand ROM socket.

ql-iss#5.jpg
QL Iss#5 Main Bord - JUx links


In the picture above I only located JU1,2,6 in the red rectangle, but manual refers to JU2,3,4. Is it just me looking at the wrong place, or a manual misreference?

Thank you.
Tomas


RWAP
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Re: All RAM chips destroyed??

Postby RWAP » Sun Apr 08, 2018 2:47 pm

tcat wrote:
In the picture above I only located JU1,2,6 in the red rectangle, but manual refers to JU2,3,4. Is it just me looking at the wrong place, or a manual misreference?

Thank you.
Tomas


No - the picture shows JU1 to JU6 - you can only read JU1, JU5 and JU6 because the writing is not obscured by the resistors...


martyn_hill
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Re: All RAM chips destroyed??

Postby martyn_hill » Sun Apr 08, 2018 3:00 pm

Hi again Tomas

As Rich said, the other positions of optional links are obscured by those three zero-ohm 'resistors' (note the single black-band == zero ohms).

It apparently proves easier to automate the component assembly process using zero-ohm resistors rather than actual bare wires...

The links in place in the picture are the appropriate configuration to match the ROMs.


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Cristian
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Re: All RAM chips destroyed??

Postby Cristian » Mon Feb 11, 2019 9:29 am

---Repair progress update---
The MC1377P RGB to PAL/NTSC (highlighted in yellow) has been swapped/tested with another QL (iss.6). It seems to work normally. The working MC1377P from the functional QL does not affect the behaviour of the faulty QL.
Even if the MC1377P still gets warmer in the faulty QL, we can say that the problem must be elsewhere.

repair-status.jpg



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