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Toshiba 3450 Fax - need Service Manual

I need a service manual or at least schematic for the main board of a Toshiba 3450 Fax machine.

Not available from Tritronics, Herman's, or Vance-Baldwin - apparently Faxes are made by a different division of Toshiba than their A/V stuff. The model was not listed on any of the on-line fax parts dealers I tried. Calling Toshiba directly, I just got the runaround, just being told to call different numbers - no one actually said they didn't have the manual - just didn't have a clue as to how to get it. I have a collection of 8 or 9 different phone numbers I was passed around to over a 2 day period.

Problem with the machine is it's basically dead. Thought it would be a simple power supply problem, ESR'd the caps in the PS, found an open 0.33 uF electrolytic, replaced with three 0.1s. Machine still dead, but have +5, +/-12, and +24 volts from PS. One output is relay switched, and never turns on. I don't know if there should be any additional output voltages from the PS. Have clocks and data activity on the uP (Z8002), but nothing on LCD except a faint row of blocks on the top line of the display, no other signs of life.

Mike WB2ME

Reply to
michael.w.appenzeller
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What kind of past history before the fail? Lightning, dropped, in storage for years or found it in the dumpster?

You could have bad solder on the main CPU chip....or even on the display, especially if there are signs of a liquid spill. Try flexing or vibrating the board for possible intermittents. Can also try powering up the unit while holding the send key, or other keys in hopes it does a system reset, in case something got corrupted. Sometimes there is a battery too that is soldered in and can cause loss of cpu operations.

Reply to
Cobalt

Cobalt,

Thanks for the reply. The machine in question was basically intercepted on its way to the dumpster, then in storage about 2 years.

The unit doesn't appear lightning damaged, it has rather impressive surge protection built-in, including low current fuses on the phone line input, and the power supply appears functional. I don't know if all the voltages are present, though. The PS plugs directly onto the motherboard, and is inaccessible when installed (component side of PS board facing into machine, solder side covered by sheet- aluminum heat sink). I didn't power up the supply outside of the machine as I was afraid of damaging it without a load. Now that I've powered it up in the machine, and have voltages at some of the connector pins, I know what pins have what voltages, so I may pull the PS and power it up with a load on the 5V line.

There is a ni-cad battery (3 button cells in series), and it was dead. I charged it with my bench power supply, and although it won't hold a charge, it gets 5V across it when the machine is on. I doubt they would have used a ni-cad battery to back up the unit's operational firmware- probably just holds user settings and keeps the clock running. There is a UV-EPROM in there, which probably has the operating firmware.

The machine doesn't appear sensitive to vibration, and the main board is a very rigid 4-layer board that doesn't flex, soldering looks excellent. I tried resetting the CPU by grounding the Reset pin on the uP - if that doesn't reset it, nothing will. Although this is a compact, entry-level Fax, comparable in features to the $99 specials in the office supply superstores, the electronic & mechanical build quality is impressive, like what you'd see in high-quality pro or industrial equipment, so it's worth putting a little effort into fixing it, just need more information.

Mike WB2MEP

Reply to
WB2MEP

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