Table of Contents

Chips from Tube Time (Eric) / EMSL (Windell) ⇒ TTEMSL

Above: TTEMSL numbering / original lot

Above: chips I got w/ my numbering, trying to preserve the original labels. 4/6 were especially hard to read, and it seems like things may have diverged

zscn

e-mail I sent:

As best as I can read your labels. They are now marked using a paint pen which is resistant to both general rub off and decapping process

Note: S4/S6 are the lasered chips. These had less clear labels but I'm calling S4 the heavily lasered one and S6 the less heavily lasered one

S4 reads a mostly uniform resistance due to severe laser damage. Therefore, it cannot be compared to anything

All remaining parts consistently cannot drive reverse current on pins 5, 35, and 36 (ie could not put current through the ESD diodes). This appears to be consistent with 6502 pinout, meaning these are all likely 6502 of some sort, or at least were bonded like one

While S3 does have relatively similar signature to the other parts, it shows significant divergences

S1, S2, and S5, and S6 read relatively close. However, I see some issues such that S2 is out of spec on pin 2, 9 and 23. Possibly indicates ESD damaged part? The other 3 are close enough that differences could just be due to manufacturing variances.

Package thickness

Observation: S1 was milled to about 0.043“. Typically this is a safe depth, with wires not appearing until at least 0.050” down. However S1 had the wires exposed at this point

Theory: packages were sanded prior to remarking. Maybe this caused the depth creep up

Result: probably not. Only very slight amounts were removed. While this may have contributed slightly, the wires and die are likely just higher (maybe unusually thick paddle). They do have gold leadframe which is uncommon

Are:

  • 1: 0.149
  • 2: 0.149
  • 3: 0.152
  • 4: 0.150
  • 5: 0.153
  • 6: 0.145

Decap

Above: black top showing. Other chips had this too

Sample Page Package Package label Die Die label Note
1 Minor endmill damage
2 Link pack_top.jpg die.jpg MOS
6502D
3 Link pack_top.jpg die.jpg MOS
6502D
Counterfeit?
Severe corrosion during decap, suspect poor overglass quality
4 Severe damage from laser
5 3020
0202
6 Link R6502F R650
 
mcmaster/iffy_6502.txt · Last modified: 2018/03/24 06:53 by mcmaster
 
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