Datasheet 4116 memory chips; searching for Sinclair ZX Spectrum parts

[[email protected]]

Hello,

I'm suffering from the well known Blinking Coloured Blocks Problem
(BCBP) on my 48K Sinclair ZX Spectrum. The 12V, 5V and -5V lines seem
ok, 7805 regulator seems ok, ULA is 100% ok (put it in a different
machine). Changed an electrolytic capacitor that had some slight
damage.

Last one in the list (not looking forward to desolder these ones), are
the 4116 16K base memory chips... But where to find replacements
(peferrably in the Netherlands)? I also might want to change the
transistors T4 and T5 (ZTX types), but I have not found these as
well...

One electronics shop offered me as a replacement for the STC4116-2N
memory chips: the MCM4116BP15, but I can't find any information /
DATASHEET on both, so I have no idea if this replacement is ok? The
only thing I can find in ZX Spectrum 48K service manuals is that the
type should be 4116 and 150ns and I know 8 of these make up 16K with
multiplexed switching of an address line to address the memory
location...


Any help, pointers, datasheets and parts highly appreciated!

George

 

[Brane2]

[email protected] wrote:

I used to replace 4116 with 6164, ofcourse after disconnecting extra
power lines and fixing them to appropriate spot, like GND. Not really
high on aestetics and authenticity points, but it worked...

 

[n cook]

Hello,

I'm suffering from the well known Blinking Coloured Blocks Problem
(BCBP) on my 48K Sinclair ZX Spectrum. The 12V, 5V and -5V lines seem
ok, 7805 regulator seems ok, ULA is 100% ok (put it in a different
machine). Changed an electrolytic capacitor that had some slight
damage.

Last one in the list (not looking forward to desolder these ones), are
the 4116 16K base memory chips... But where to find replacements
(peferrably in the Netherlands)? I also might want to change the
transistors T4 and T5 (ZTX types), but I have not found these as
well...

One electronics shop offered me as a replacement for the STC4116-2N
memory chips: the MCM4116BP15, but I can't find any information /
DATASHEET on both, so I have no idea if this replacement is ok? The
only thing I can find in ZX Spectrum 48K service manuals is that the
type should be 4116 and 150ns and I know 8 of these make up 16K with
multiplexed switching of an address line to address the memory
location...


Any help, pointers, datasheets and parts highly appreciated!

George

I've hundreds of them
ET 4116N-3 datecoded 1983
About 2 for 1 Euro plus p&p for about 20 off

 

[[email protected]]

One electronics shop offered me as a replacement for the STC4116-2N
memory chips: the MCM4116BP15, but I can't find any information /
DATASHEET on both, so I have no idea if this replacement is ok? The
only thing I can find in ZX Spectrum 48K service manuals is that the
type should be 4116 and 150ns and I know 8 of these make up 16K with
multiplexed switching of an address line to address the memory
location...

You should be fine using 150nS chips (as you were offered by the shop)
instead of 200nS chips (the ones in your computer). Someone else responded
to your message that he has 300nS chips in stock, I think those would be
too slow.

 

[Gerard Bok]

You should be fine using 150nS chips (as you were offered by the shop)
instead of 200nS chips (the ones in your computer). Someone else responded
to your message that he has 300nS chips in stock, I think those would be
too slow.

No

That someone offered 4116-3 chips.
4116-2 = 120 nsec access time
4116-3 = 90 nsec
4116-4 = 70 nsec

(UMC 1986 Memory databook. I got suspicious.
300 nsec was the slowest part, back in 1979. It would be odd that
someone would still be stamping them out in 1983

A word of warning: I recall some early Sinclairs to be a real
menace to desolder. Holes that are tight enough to serve as
sockets, even without solder

 

[Brane2]

A word of warning: I recall some early Sinclairs to be a real
menace to desolder. Holes that are tight enough to serve as
sockets, even without solder

That's why god invented OLFA knife. Just press the knife vertically at
the spot where pin enters the plastic housing and just a bit along the
edge of plastic and cut it off.

After cutting all the pins just heat them and pull them off one by
one...

 

[n cook]

I've hundreds of them
ET 4116N-3 datecoded 1983
About 2 for 1 Euro plus p&p for about 20 off

Also 14 pages of data for the Mostek 1980 version of 4116

 

[[email protected]]

That someone offered 4116-3 chips.
4116-2 = 120 nsec access time
4116-3 = 90 nsec
4116-4 = 70 nsec

Okay, weer wat geleerd... I was thinking of the codes on later DRAM
chips, not knowing they used another system on these.

A word of warning: I recall some early Sinclairs to be a real
menace to desolder. Holes that are tight enough to serve as
sockets, even without solder

A possible trick would be to cut off the legs of the old IC's, then
unsolder them one-by-one.

 

[GdB]

Hello,

So, these "ET 4116N-3 datecoded 1983" memory chips should be fine? So,
if the number of nanoseconds is LOWER, it is never a problem; if it's
higher then it is a problem??? Most important thing for me to know is,
if these chips from N. Cook / Diverse Devices will work...

I don't know exactly what is expressed in this timing/frequency... I
thouht it had something to do with refresh rate, but then a refresh
needed every 150ns sounds better than refreshing every 90ns...

Maybe someone has an old datasheet, I'll search for the 2118 to see
what it is.

Any pointers to the ZTX213, 313 and 650 transistors?

Kind regards,


George



[email protected] schreef:

 

[Bart Jorritsma]

Hi,

That's why god invented OLFA knife. Just press the knife vertically at
the spot where pin enters the plastic housing and just a bit along the
edge of plastic and cut it off.

After cutting all the pins just heat them and pull them off one by
one...

To speed up difficult repairs you can also let the pins that are cut off
in the pcb if there's enough space, sometimes better to prevent heating
damage when clearing the empty holes. This method used a few times when
replacing (TXT) chips on the digital signal processing module of D16
chassis television sets (repeatedly flashing wrong (txt) picture will
mostly be the symptom then).


succes, greetings Bart


PS: if availability is a problem i have the chips possibly also, but not
nearby (except the same type is used on an IBM 286 6Mhz AT system
board.........., around 32 chip positions with 2 paralelled chips
per position for increased fan-out.......)

 

[n cook]

Hello,

So, these "ET 4116N-3 datecoded 1983" memory chips should be fine? So,
if the number of nanoseconds is LOWER, it is never a problem; if it's
higher then it is a problem??? Most important thing for me to know is,
if these chips from N. Cook / Diverse Devices will work...

I don't know exactly what is expressed in this timing/frequency... I
thouht it had something to do with refresh rate, but then a refresh
needed every 150ns sounds better than refreshing every 90ns...

Maybe someone has an old datasheet, I'll search for the 2118 to see
what it is.

Any pointers to the ZTX213, 313 and 650 transistors?

Kind regards,


George



[email protected] schreef:

Okay, weer wat geleerd... I was thinking of the codes on later DRAM
chips, not knowing they used another system on these.


A possible trick would be to cut off the legs of the old IC's, then
unsolder them one-by-one.

Well they're all in original storage tubes, just old stock, stored indoors.
Geometries those days not so prone to cosmic ray damage over time.

 

[Eric Rullens]

Hello,

...

I don't know exactly what is expressed in this timing/frequency... I
thouht it had something to do with refresh rate, but then a refresh
needed every 150ns sounds better than refreshing every 90ns...

...

Usually refresh rates are in the ms range (and are not stamped on the chip),
access times are in the ns range.

Eric

 

[ian field]

Hello,

So, these "ET 4116N-3 datecoded 1983" memory chips should be fine? So,
if the number of nanoseconds is LOWER, it is never a problem; if it's
higher then it is a problem??? Most important thing for me to know is,
if these chips from N. Cook / Diverse Devices will work...

I don't know exactly what is expressed in this timing/frequency... I
thouht it had something to do with refresh rate, but then a refresh
needed every 150ns sounds better than refreshing every 90ns...

Maybe someone has an old datasheet, I'll search for the 2118 to see
what it is.

Any pointers to the ZTX213, 313 and 650 transistors?

Kind regards,


George



[email protected] schreef:

Okay, weer wat geleerd... I was thinking of the codes on later DRAM
chips, not knowing they used another system on these.


A possible trick would be to cut off the legs of the old IC's, then
unsolder them one-by-one.

When I googled "ztx650" the first hit was the pdf datasheet! When I googled
"ztx213 pdf" I got a link to the Sinclair spectrum service manual, I think
the ztx213 etc are fairly commonplace specifications say around 0.3A 45 or
so volts and hfe about 2 or 3 hundred.

 

[[email protected]]

ZTX213

= BC213, universal PNP, replaceable by BC557

ZTX313

= BSV26, low power switching NPN, replaceable by BSX20 or 2N2369

ZTX650

lo-sat 60V 2A NPN, replaceable by 2SC3328, 2SD1207 or 2SD1835

 

[DizTRacT]

Those are static memory chips, which don't need or use refresh.
That's why the type is called static (in contrast to dynamic, which do
need refresh).
The numbere of ns stand for access time for these chips.
(the minimum time needed before a stable output signal is available.)
So lower numbers are always allright in this case.

Hello,

So, these "ET 4116N-3 datecoded 1983" memory chips should be fine? So,
if the number of nanoseconds is LOWER, it is never a problem; if it's
higher then it is a problem??? Most important thing for me to know is,
if these chips from N. Cook / Diverse Devices will work...

I don't know exactly what is expressed in this timing/frequency... I
thouht it had something to do with refresh rate, but then a refresh
needed every 150ns sounds better than refreshing every 90ns...

Maybe someone has an old datasheet, I'll search for the 2118 to see
what it is.

Any pointers to the ZTX213, 313 and 650 transistors?

Kind regards,


George



[email protected] schreef:

Groeten,
- DizTRacT -

Ik wil niet genieten, ook niet met mate


Voor antwoord per e-mail, eerst ".DitNieT" uit het adres verwijderen !

 

[Eric Smith]

Those are static memory chips, which don't need or use refresh.

No, the 4116 is NOT a static memory. It's dynamic.

I don't know exactly what is expressed in this timing/frequency... I
thouht it had something to do with refresh rate, but then a refresh
needed every 150ns sounds better than refreshing every 90ns...

It's the access time. 90 ns is better than 150 ns.

The refresh time is one complete refresh every 2 ms, regardless of the access time.

 

[Franc Zabkar]

I'm suffering from the well known Blinking Coloured Blocks Problem
(BCBP) on my 48K Sinclair ZX Spectrum. The 12V, 5V and -5V lines seem
ok, 7805 regulator seems ok, ULA is 100% ok (put it in a different
machine). Changed an electrolytic capacitor that had some slight
damage.

Last one in the list (not looking forward to desolder these ones), are
the 4116 16K base memory chips...

A colleague once showed me a clever trick. You can sometimes identify
the faulty DRAM without desoldering it by piggybacking a known good
DRAM on top of it. Despite my skepticism the technique worked.

- Franc Zabkar

 

[Franc Zabkar]

[email protected] wrote:

I used to replace 4116 with 6164, ofcourse after disconnecting extra
power lines and fixing them to appropriate spot, like GND. Not really
high on aestetics and authenticity points, but it worked...

Don't you mean 4164? The 6164 is an 8Kx8 SRAM whereas the 4116 is
16Kx1.

- Franc Zabkar

 

[Mike Wynne]

A colleague once showed me a clever trick. You can sometimes identify
the faulty DRAM without desoldering it by piggybacking a known good
DRAM on top of it. Despite my skepticism the technique worked.

That works. Also, sometimes you can find the faulty chip by sticking your
finger on each DRAM in turn and seeing if any are noticably hotter than the
others.

MikeW

 

[Brane2]

Don't you mean 4164? The 6164 is an 8Kx8 SRAM whereas the 4116 is
16Kx1.

True. My bad. I meant 4164. It would be kinda hard to squeeze 6164 as a
pin compatible replacement without a hacksaw and some heavy magic ;o)