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Tandon TM100-2 - correct terminator and jumper settings?

P

pjhacnau

Experienced Member
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Apr 5, 2015
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Location
Morisset, NSW Australia
I recently picked up a TM-100-2A, with a view to it being an extra external drive for the M4 &/or the M1. Purchase was partly motivated by the drive I use for the M1 (Texas Peripherals) stopping working. The drive was advertised as needing a realignment, and I'd love to get to that but . . .

First, it is missing the terminating resistors. No big problem, searching around led me to here, where they stated that an appropriate replacement was an 899-3-R150. Which I duly ordered 2 of. They also said that the resistor was 14 pin . . . it was only when I went to fit one today that I bothered counting the number of pins in the socket (F2) :oops:. Which is 16. And at my regular "odd pieces" store (Rockby) I can't find a 16-pin 8-resistor chip at 150 ohms. 16-pin 15-resistor yes, but my understanding is the terminator should be the 1-resistor-across-two-pins form
Can someone point me to a correct model of resistor network? And an Australian-based store selling them?

While I have your attention, someone specifying the correct jumper setup for socket 1E as a single drive? I would guess that only DS0 should be jumpered, but the drive came out of an XT and has everything except HM jumpered - would that work if left as-is?

TIA

PJH
 
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Bourns 4116R-1-151LF or
Dale MDP1603150RGD04

will work. There are probably others, but Mouser has them in stock.

You can also fudge one up by taking a 16 pin DIP header and soldering individual 150 ohm resistors side-by-side.
 
pjhacnau said:
First, it is missing the terminating resistors. No big problem, searching around led me to here, where they stated that an appropriate replacement was an 899-3-R150. Which I duly ordered 2 of. They also said that the resistor was 14 pin . . . it was only when I went to fit one today that I bothered counting the number of pins in the socket (F2) . Which is 16.
Click to expand...
My fault. The web page has been fixed.

pjhacnau said:
And an Australian-based store selling them?
Click to expand...
If you PM me your postal address, I will freely send to you, two 898-3-R150 from my spares.
 
I've now got the drive working. As pointed out adding a 150R to the 899-3-R150 to cover the last 2 pins works for termination. However it still wasn't being selected. I discovered the problem when I decided to put an 8-way DIP switch in socket 1E. The jumper block in there looked like it was a simple 7 jumper block, with all 7 intact (meaning everything except HM was selected). At least it looked like that from the back of the drive, and from the top. When I pulled it, I discovered the other side had only one pin. So all that was selected was DS1. Which would have been fine in it's original role as drive B in a 5150. And would also explain why it wasn't selected when connected to either my M1 or M4. With the DIP switch in place and DS0-3 all selected, it suddenly worked.

I thought I'd report my experience with the jumper block as a "trap for the unwary".

Anyway, I can now get ready for the fun of alignment.

Thanks Chuck and modem7 for the comments.

PJH
 
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Chromedome45 said:
Hey PJH, That was discussed earlier in this thread: http://www.vcfed.org/forum/showthread.php?53426-Dual-Tandon-TM100-1A-Configuration-for-Model-1 look at post #6 where I informed the OP to enable all drive selects if using the RS cable with the pin pulls using a Tandon TM-100-1a.
Click to expand...

Yep I saw that. The problem here was the jumper block fooled me into thinking they were selected. It was only when I pulled it that I saw that only DS1 was actually selected.

PJH
 
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