or model AD-L528, 2 labels from cold , a part second, partial feint display on the fluorescent, then nothing. All voltages agree with legends of 3.3,5,12,-20V dc and 4.4V ac to the display. Standby voltage of 2.1V on switching power on. Anyone know what the RAT of designator RAT5V stands for as it is only 1.4V on one of the lines to/from? the ps
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
On Mon, 18 Feb 2008 15:52:51 -0000, "N Cook" put finger to keyboard and composed:
Which chipset does it use?
- Franc Zabkar
-- Please remove one 'i' from my address when replying by email.
1.4V
My measurement at fault RAT5V has 5V to the display/front controls board with a PT6311 but no bus signals to it from the main board. Main board main chip has a bonded heatsink over it, Winbond 130 WG , CS4955 etc, but no activity on the board. About 60 electrolytics and no IC protectors spied and likes of basic LM1458 have correct DC.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
There is a blcok diagram and a hand-drawn psu circuit (a bit too blurry) at:-
Geo
then
LM1458
The heatsink will twist off the main chip quite easily. Crystal CS98010CMEP all electros check out
27MHz oscillation at the crystal oscillator and 5V is passed through the gatekeeper KIA70 31AP and 3.3V rail is continuous to the Crystal chip-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
1.4V
at:-
I tried googling but you must be more expert, quite a bit of useful data there. Seems quite charming to see a hand-drawn circuit diagram for a high tec piece of kit
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
1.4V
at:-
I wonder if it can be a software bug That site mentions
"On occasion unit will power on with no life at all - no standby LED"
with no mention of a reason/solution. If it means dead without even the unit's display lit and no Standby LED then that is what is here but permanently.
I've tried the factory reset sequence mentioned there.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
On Tue, 19 Feb 2008 11:11:21 GMT, Geo put finger to keyboard and composed:
It appears that PQ30RV21 (2A LDO regulator) provides the RAT5V rail:
AFAICT, the PC5V rail is derived from RAT5V by switching it via Q8 (2SB772) which is in turn controlled by Q7 and the standby signal (from the decoder board?). So if RAT5V is only 1.4V, then where is the OP's PC5V coming from? BTW, D15 seems to be drawn with the wrong polarity.
- Franc Zabkar
-- Please remove one 'i' from my address when replying by email.
then
1.4Vat:-
It was my error reading, 5V was there. Further onto the main board I thought I'd found a SM inductor on a power rail, blown as a fuse. Legend L on the overlay but measured 1.2K ohm, but numbers over the "inductor" itself said 122.
.On Tue, 19 Feb 2008 12:26:46 -0000, "N Cook" put finger to keyboard and composed:
Maybe I'm confused, but I think you'll find that's Cirrus Logic. In
1991 Cirrus Logic acquired Crystal Semiconductor.
Sorry, I don't have a reference design circuit for that chip. All I can suggest is to disconnect the IDE cable from the DVD drive to see if that is hanging up the machine.
- Franc Zabkar
-- Please remove one 'i' from my address when replying by email.
Standard linearised graphic logo of Crystal on the main chip
Yes, already tried disconnecting the deck. The owner seemed cagey , when I asked about any precepitatory events. I don't know anything about DVDs , I have no personal use for the things either. I get the impression it is possible to download software fudges to disable regionalisation etc. If the owner did this with some corrupted source could that action have caused a hardware latch-up, or do manufacturer's deliberately put a close-down function in there. ? I can see there is a disc in the drive, but I've not dismantled to remove it, (no mechanical functions, switch responses or display). If I dismantle it and find a home-blown disc , what could I infer from that?
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
On Thu, 21 Feb 2008 07:50:37 -0000, "N Cook" put finger to keyboard and composed:
Most region free procedures involve a key sequence on the remote control. Others require a disc.
If the owner botched a firmware upgrade, then I don't know how you would recover from it, unless the machine had a removeable EEPROM or EPROM, in which case you could reprogram it in a device programmer. Otherwise, if your chipset is anything like my Sunplus chipset, then you would force the CPU into "boot trap mode" (by means of a jumper) and then use an RS232C serial dongle to upload the correct firmware.
You should be able to test the IDE DVD loader in a PC. If faulty, then try replacing it with a standard IDE DVD-ROM drive, if you can make it fit. BTDT.
- Franc Zabkar
-- Please remove one 'i' from my address when replying by email.
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