Eric Bylenga

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Home > Lc475

Macintosh LC 475

LC475

This machine was given to me after having sat in storage for something like a decade. I think it was stored in a wood shop as it was covered in a fine layer of sawdust in addition to being very dusty on the inside. Yellowing on the case was moderate and internally there was a mess of leaky electrolytic capacitors as is becoming increasingly more common as Macintosh computers from the 90's age.

I attempted a boot in it's original state but I got nothing but static as a startup bong and no video on the screen. The video was caused by a dead clock battery but it was time for a re-cap anyhow so I decided to do a full restoration job from top to bottom.

Capacitor Lists

Motherboard
QtyDesignationValue
9 C35,C36,C101,C103,C127,C128,C129,C149,C150 47uf @ 16V
2 C136,C137 100uf @ 6.3V


TDK Power Supply
QtyDesignationValue
3 C5,C52,C55 1000uf @ 10V
1 C8 8.2uf @ 50V
2 C53,C54 270uf @ 25V
1 C56 56uf @ 25V
1 C60 47uf @ 25V
1 C8 270uf @ 10V


In addition to the recap I cleaned and re-greased the floppy drive, which was fairly stiff. The case I put through the dishwasher for a good clean followed up by Perifractic's air-bright technique in the hot summer sun to de-yellow the case. I have to say, after three days the case looks very much better!

Finally I upgraded the RAM from an 8MB SIMM to a 32MB SIMM for a total of 36MB RAM and swapped out the 68LC040 for a full 25MHz 68040 to round out the restoration. Boots like a dream! Last thing I'd like to do is buy a couple of 512KB VRAM SIMMs so that I can display thousands of colours at 800x600 or 640x480. Currently I can only do so with 512x384 with the default dual 256KB models. Hopefully I can find a good deal!

Oh yea, in order to get video, I plugged in one of my 3D printed battery adapters. See the link to that page below.

Benchmarks

All benchmark tests happened on System 7.6.1 using the SCSI to SD controller using Speedometer 3.23. HDD scores aren't included as the SD adapter can't reach the full speeds of the SCSI controller on the LC475.

68LC40 @ 25MHz

P.R. Results (Uses Mac Classic as 1.0):
CPU: 15.871
Graphics: 15.613
Math: 31.811
Performance Rating (OLD PR): 14.804
Performance Rating (NEW PR): 8.678

Benchmark Results (Uses Mac Classic as 1.0):
KWhetstones: 285.714 39.138
Dhrystones: 19230.769 19.737
Towers: 18.909
QuickSort: 17.758
Bubble Sort: 18.409
Queens: 18.320
Puzzle: 22.457
Permutations: 21.018
Fast Fourier: 26.503
F.P. Matrix Multiply: 27.841
Integer Matrix Multiply: 24.200
Sieve: 23.362
Benchmark Average: 23.138

No FPU present. No tests were run.





Color Tests (Uses Mac II as 1.0):
Black & White: 4.967
4 Colors: 5.287
16 Colors: 5.444
256 Colors: 5.539
Color Test Average: 5.309
68040 @ 25MHz

P.R. Results (Uses Mac Classic as 1.0):
CPU: 15.727
Graphics: 16.116
Math: 101.184
Performance Rating (OLD PR): 21.829
Performance Rating (NEW PR): 8.821

Benchmark Results (Uses Mac Classic as 1.0):
KWhetstones: 1428.571 195.694
Dhrystones: 19230.769 19.737
Towers: 18.909
QuickSort: 17.166
Bubble Sort: 18.837
Queens: 19.083
Puzzle: 22.457
Permutations: 21.018
Fast Fourier: 123.589
F.P. Matrix Multiply: 127.196
Integer Matrix Multiply: 24.200
Sieve: 23.362
Benchmark Average: 52.604

FPU Tests (Uses Mac II as 1.0):
FPU Fast Fourier: 10.733
FPU KWhetstones: 4000.000 5.600
FPU F.P. Matrix Mult.: 11.025
FPU Test Average: 9.119

Color Tests (Uses Mac II as 1.0):
Black & White: 4.954
4 Colors: 5.251
16 Colors: 5.433
256 Colors: 5.530
Color Test Average: 5.292


Current Specifications

Processor: 25Mhz 68040
FPU: Built-in
RAM: 36MB, 4MB on motherboard plus 32MB 72Pin 70ns DRAM SIMM
HDD: 16GB SD Card on SCSItoSD 5.0b card.
Floppy: 1.4MB Superdrive
Internal Expansion: LC PDS Slot (populated with PDS ethernet card)
External Expansion: DB-25 SCSI, ADB, DIN-8 RS-422 Serial x2, Audio-In, Audio-Out, Mac VGA 15pin
Battery: 3.6V Lithium
Gestalt ID: 89
Production Dates: October 21, 1993 - May 1, 1994
Original Price: $1085 USD
Size (HxWxD): 2.9" x 12.2" x 15.3"
Weight: 4kg
Part #: M1476
OS: 7.6.1 (currently installed)

Links

3.6V 1/2 AA Lithium Clock Battery Replacement
Retrobrighting with Just Sun?

Last Updated September 21, 2019