Hello,
I have a PM-7200 which doesn't power on. Using a working PM-7200, I've narrowed the problem to the front control panel which contains a Toshiba TMP87PH46N IC. One of its jobs is to fire the relay on the AC inlet and I suspect the chip itself is at fault but will confirm this with testing for 5vdc in.
I contacted Marantz's official parts supplier, Sontec but they say the Toshiba is no longer available. I can source the chip on eBay put I presume as a P-ROM, i'll only be buying a blank chip, without the necessary instructions for the PM-7200?
Can anyone shed light on where I could pick up one up?
Many thanks.
I have a PM-7200 which doesn't power on. Using a working PM-7200, I've narrowed the problem to the front control panel which contains a Toshiba TMP87PH46N IC. One of its jobs is to fire the relay on the AC inlet and I suspect the chip itself is at fault but will confirm this with testing for 5vdc in.
I contacted Marantz's official parts supplier, Sontec but they say the Toshiba is no longer available. I can source the chip on eBay put I presume as a P-ROM, i'll only be buying a blank chip, without the necessary instructions for the PM-7200?
Can anyone shed light on where I could pick up one up?
Many thanks.
This Marketplace website has it but they originate from Hong Kong-
TMP87PH46N TOSHIBA Semiconductor CORPORATION, TMP87PH46N Datasheet
Or how about India ?
Integrated circuit - Toshiba TMP87PH46N Integrated Circuit Wholesale Trader from Delhi
I am NOT recommending them but as its obsolete .
Hold on this looks like a kosher US company -
TMP87PH46NG - TOSHIBA - IC Chips - Kynix Semiconductor
TMP87PH46N TOSHIBA Semiconductor CORPORATION, TMP87PH46N Datasheet
Or how about India ?
Integrated circuit - Toshiba TMP87PH46N Integrated Circuit Wholesale Trader from Delhi
I am NOT recommending them but as its obsolete .
Hold on this looks like a kosher US company -
TMP87PH46NG - TOSHIBA - IC Chips - Kynix Semiconductor
This might work:
1. Buy a blank TMP87PH46N (there is no way to erase them, so a TMP87PH46N programmed with some other program will be useless)
2. Remove the good TMP87PH46N from the working PM-7200
3. Build the circuit from Figure 1-3 of the datasheet, TMP87PH46N pdf, TMP87PH46N description, TMP87PH46N datasheets, TMP87PH46N view ::: ALLDATASHEET :::
4. Use a 1980's/1990's style EPROM programmer that can read and write 27256 EPROMs (people interested in historic electronics may still have one of those) to copy the data from the good to the blank device. Mind the correct programming voltage, I found out the hard way that different programming voltages were used for the 27256!
5. Put the good device back where it came from and put the freshly programmed device in the nonfunctional PM-7200
As an alternative, you could also check if someone from a UK historic electronics organization happens to have one. For example, if you were Dutch, I'd recommend posting on Nederlands Transistorforum
1. Buy a blank TMP87PH46N (there is no way to erase them, so a TMP87PH46N programmed with some other program will be useless)
2. Remove the good TMP87PH46N from the working PM-7200
3. Build the circuit from Figure 1-3 of the datasheet, TMP87PH46N pdf, TMP87PH46N description, TMP87PH46N datasheets, TMP87PH46N view ::: ALLDATASHEET :::
4. Use a 1980's/1990's style EPROM programmer that can read and write 27256 EPROMs (people interested in historic electronics may still have one of those) to copy the data from the good to the blank device. Mind the correct programming voltage, I found out the hard way that different programming voltages were used for the 27256!
5. Put the good device back where it came from and put the freshly programmed device in the nonfunctional PM-7200
As an alternative, you could also check if someone from a UK historic electronics organization happens to have one. For example, if you were Dutch, I'd recommend posting on Nederlands Transistorforum
Hey thanks for the help. Wouldn't these be blank chips, though? I presumed I would need one programmed with the PM-7200's instructions. Blank chips are available in the UK. It's the programmable data that's the tricky part:
TMP87PH46N TOSHIBA INTEGRATED CIRCUIT ''UK COMPANY SINCE1983 NIKKO''UK STOCK'' 5052406135027 | eBay
Hmm, yes, way cool idea. I used to burn PIC12C508A chips back in the days of the PlayStation 1 with an EPROM burner. I'll investigate.
Many thanks.
I have found this is a common fault with Marantz ,one guy sent it to Richer Sounds in 2014 ,they admitted they couldn't programme a new chip --it took the guy weeks before they admitted it.
But your right if the microprocessor is faulty then no power.
I cant find anybody --so far --who will program this 8 bit chip.
But your right if the microprocessor is faulty then no power.
I cant find anybody --so far --who will program this 8 bit chip.
At best, I've found a commonly used 40 pin programmer at a reasonable cost but I'd need a 42 pin adapter - Minipro TL866II Plus EPROM Programmer | eBay
There are a lot of Toshiba chips on the EPROM burner's compatibility list although not quite this one, which makes sense since it would physically fit anyway. If I can get the adaptor, I could be in business, reading the working chip and burning a new one. Looking at the Toshiba's datasheet, not all 42 pins are needed in program mode.
Cool, thanks for your help. The service manual seems to be indicating a 4.00 mHz ceramic resonator but the one on the board seems to be a Murata 8.00mHz one and this is consistent with Murata's spec sheets.
Attachments
Thanks, I see that. It's the schematic for the now obsolete BM1193 adaptor but I can't lie, it's a little beyond my skillset. I can follow pinouts but I don't understand how port numbers relate to them. If I can figure it out or find someone to build it for me, then yay, I should be OK with the TL866 II programmer.
If you don't have a 'scope to test it, it's worth replacing it anyway as they are cheap and easy enough to get
In the figure on the first page of the datasheet, you see what port number of the microcontroller corresponds to what pin. For the connection to the programmer, you also need to know the pinout of a 27256, which you can find here: https://ist.uwaterloo.ca/~schepers/ROMS/PINOUTS/27256.png
First try the resonator, though!
If changing the resonator doesn't help, it may also be useful to check the circuitry connected to pin 18 (active-low reset) of the TMP87PH46N. I fixed an amplifier a long time ago that also had a microcontroller that didn't work and it turned out to be due to it not being reset properly.
If I understand this datasheet of a related microcontroller (probably the mask ROM version) properly, Datasheet Archive 87c846 datasheet download , which is a big if as it is in Japanese, pin 18 has a built-in pull-up resistor between 100 kohm and 450 kohm. The external application circuit may then simply be a capacitor to ground, but if it happens to be a dried-out electrolytic capacitor, you get no reset.
If I understand this datasheet of a related microcontroller (probably the mask ROM version) properly, Datasheet Archive 87c846 datasheet download , which is a big if as it is in Japanese, pin 18 has a built-in pull-up resistor between 100 kohm and 450 kohm. The external application circuit may then simply be a capacitor to ground, but if it happens to be a dried-out electrolytic capacitor, you get no reset.
Yikes! I better check that. I'll need to disassemble the front panel to check. I hope so. The working one I imported from Germany, the broken one is UK.
I think I understand you - the Japanese text to the left of the resistance values of Min 100, Typical 220, Max 450 Ohms comes up on Google translate as Input Resistance.
Following the tracks on the board, Pin 18 goes to the emitter of a TO-92, out of the collector and into the negative side of an electrolytic 50v 22uF. I'll test it in the multimeter to see if it's still alive.