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Mystery TM 504 screws.


Colin Herbert
 

Can anyone shed some light on this mystery? I was carrying out some repairs to my TM 504 mainframe, I noticed that there was a particular screw missing. I further noticed that an eBay seller (from who I had purchased before and was sure of their honesty) was selling these screws. On checking in my TM 504 Service Manual (ID# 070-1716-00) I ascertained that the description of the screws in the manual and on the seller's listing were substantially identical. The eBay listing was:

211-0040-00 TM 504 Plastic Screws 4-40 x .25"

The Manual has:

211-0040-00 SCREW, MACHINE: 4-40 x .25", BDCH PLSTC

The manual also shows in Fig. 2 Exploded that these screws are attaching a frame section and that nine are required.

This is where the mystery starts. The screws actually in place on my TM 504 are steel, countersunk head and of a much greater diameter than the plastic ones (which is what you might expect). Does anyone have any idea of what these plastic screws are for and how did such an anomaly happen in the TM 504 Service Manual?
TIA, Colin.


teamlarryohio
 

My manual (same) shows 212-0040-00 are used in many places. I'd bet on a typo.
-ls-


Colin Herbert
 

A typo on the diagram could just be the answer. The problem is that while I can credit that 212-0040-00 is the correct screw for where "9" is labelled on the diagram, there are only nine called out in the list, when twice this number is actually required. Perhaps whoever compiled that part of the manual had a "liquid lunch" on a Friday - it's a typo upon a typo.

It still leaves the puzzle of what the little plastic screws are meant for....
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of teamlarryohio
Sent: 05 August 2020 14:35
To: TekScopes@groups.io
Subject: Re: [TekScopes] Mystery TM 504 screws.

My manual (same) shows 212-0040-00 are used in many places. I'd bet on a typo.
-ls-


teamlarryohio
 

You were looking at item 9. The others are item 39...no clue what uses the plastic ones.
-ls-


Colin Herbert
 

Yeah, I checked in my manual and found that they were item 39.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of teamlarryohio
Sent: 05 August 2020 18:27
To: TekScopes@groups.io
Subject: Re: [TekScopes] Mystery TM 504 screws.

You were looking at item 9. The others are item 39...no clue what uses the plastic ones.
-ls-


Dave Seiter
 

I refurbed a pile of TM503 through TM506 a while back, and don't recall any plastic screws.  Seems to me the only place you'd need plastic on one of them would be to electrically isolate something, but even the power xstrs used steel hardware.
-Dave

On Wednesday, August 5, 2020, 05:53:08 AM PDT, Colin Herbert via groups.io <colingherbert=blueyonder.co.uk@groups.io> wrote:

Can anyone shed some light on this mystery? I was carrying out some repairs to my TM 504 mainframe, I noticed that there was a particular screw missing. I further noticed that an eBay seller (from who I had purchased before and was sure of their honesty) was selling these screws. On checking in my TM 504 Service Manual (ID# 070-1716-00) I ascertained that the description of the screws in the manual and on the seller's listing were substantially identical. The eBay listing was:

211-0040-00 TM 504 Plastic Screws 4-40 x .25"

The Manual has:

211-0040-00 SCREW, MACHINE: 4-40 x .25", BDCH PLSTC

The manual also shows in Fig. 2 Exploded that these screws are attaching a frame section and that nine are required.

This is where the mystery starts. The screws actually in place on my TM 504 are steel, countersunk head and of a much greater diameter than the plastic ones (which is what you might expect). Does anyone have any idea of what these plastic screws are for and how did such an anomaly happen in the TM 504 Service Manual?
TIA, Colin.