The Shugart SA455-3AA is a DSDD Floppy Disk Drive (360K).

The work that has been done:

• Replacement of the Electrolytic Capacitors on the Motor PCB.
• Greasing the head sliding rods with silicone grease.
• Reconstruction of the pcb track corroded by the loss of the 10uf electrolytic capacitor.
• Replacement terminals for selection with jumpers.
• Ceramic capacitor replacement.
• General cleaning.
• Read/write test with GreaseWeazle interface.

List of replaced electrolytic capacitors:

• 1 x 10uf 25v
• 1 x 47uf 16v
• 1 x 0.47uf 50v
• 1 x 0.22uf 50v
• 2 x 22uf 25v (non-polarized)

Gallery:

Download: Shugart SA455-SA465 Service Manual (70)

I decided to replace completely the PCB of the Amiga Power Supply (312503-03) because although after replacing all capacitors 1 year ago (30/4/2023) the voltages are not always stable, especially the 5V which fluctuated between 5.2v and 6.9v.

Using a Gotek HXC drive as a floppy device has burned two USB sticks, i recovered one replacing a shorted smd capacitor.

So let’s retire the old power supply pcb and welcome to the Mean Well RPT-60B fully compatible about voltage and amperage.

I leave you the Aliexpress link.

Gallery:

The usual boring replacement of all exhausted capacitors.

Gallery:

I wanted to try the SIDKick pico also with my SID Player, everything is ok, it works as well as i expected.

The green LED just below the SID Socket indicates that the SIDKick is playing.

Video:

SIDKick pico by Frenetic is a microcontroller-based C64 SID replacement. Analog inputs for paddles and mice are available just as for the original SID.

SIDKick pico uses firmware similar to its “big brother” SIDKick. However, the pico variant is based on the Raspberry Pi Pico board that uses the RP2040 microcontroller which is much cheaper and has better availability than the Teensy that is used by the normal SIDKick.

Technical features:

• Dual 6581 and/or 8580 emulation based on reSID 0.16 (optional: extension for digi-playing techniques).
• 2nd-SID address at $d400, $d420, $d500, $d420 + $d500 simultaneously, $de00, $df00 ($d500 is not available on the C128), or any address when an external chip select signal is used (e.g. on Ultimate 64 boards).
• Paddle/Mouse support.
• Built-in configuration menu (launch with “SYS 54301″/”SYS 54333″, also from C128-mode).
• Sound output via PWM (mono) through the C64/C128 mainboard, or in stereo using a PCM5102A-DAC-board.
• Flashing RGB-LED (WS2812) on GPIO 23 (installed on some Pico-clones)

My personal opinion:

My personal opinion as an inveterate purist is that no emulation or implementation will have the sound performance of the native SID (6581/8580).

I can accept as a good implementation the FPGASid and ARMSid where the developers have done a really good job.

SIDKick defends itself well and is low cost, furthermore it’s Open Source, also has a nice feature that i appreciated a lot, it has integrated configuration software that can be run with a simple SYS in both C64 and 128 modes.

So my final opinion is most people will never notice any difference, but i assure you that the differences are there, so i recommend it to everyone unless you are a SID purist.

Note:

The audio output and emulation improves if you use the PCM5102A-DAC add-on card, in my test i chose not to use it because i wanted to show you a plug’n'play without too many cables, jacks and patches. Maybe it was better to include this additional module directly on the SIDKick PCB? probably yes.

The KIT was purchased from restore-store.de, fast shipping and impeccable service.

Gallery of the shipping box:

Gallery:

Video:

source: c64-wiki.com github.com/frntc/SIDKick-pico restore-store.de

The First Amiga Intro by Lynx/Nightfall.

It only took just under two months to learn from scratch 68k Assembler and Amiga Custom Chip registers.

Well done Lynx!

Download: Retro Love Intro by Lynx/Nightfall (301)

source: pouet.net

First of all, i thank my friend Gerben for giving me the monitor.

This is a Black and White monitor but for some reason a thin transparent film has been applied to the front of the cinescope to simulate the tonality of an amber cathode ray tube, furthermore the APF logo placed on the front of the monitor to the right of the power light is masked.

The TVM-10 APF Monitor is approximately 43 years old and was used with the Computer APF Imagination Machine I/II.

The Monitor had several functioning problems, below is the description of the work that has been done.

• Removing the colored film.
• Replacement of all electrolytic capacitors.
• Replacement of a ceramic capacitor.
• Horizontal synchronism calibration (H-HOLD) by delicately removing the wax that was melted inside the variable inductor.
• Installation of a 1uf polyester capacitor in parallel with the 1.5uf one present for width adjustment horizontal (H-WIDTH) of the image, unfortunately the ferrite core inserted into the variable inductor for manual adjustment is blocked, probably with glue, forcing is not a good idea.
• Check of the Diodes.
• Calibration using the trimmer placed on the front of the PCB of the monitor for the power supply voltage which must be 12v.
• Geometry adjustment.
• General cleaning.

Only one geometry problem remains; the image on the top left side of the CRT tends to bend slightly for about 1cm and the left side of the image is slighty rounded, problem surely attributable to some polyester capacitor or resistance that has lost the capacity/value of the time.

Needless to say i checked almost all the polyester capacitors and resistors in the horizontal section and didn’t find nothing scandalous.

The photo gallery contains all the photos i made during the repair, i take this opportunity to thank a user of the plcforum who gave me tips on how to proceed with the repair.

Gallery of the repair:

123►

Apple ][ EuroPlus Repair.

Defects:

• Black screen.
• Power light off.
• Keyboard does not work.

Repair:

About the black screen it was enough to press all the IC in their seat, i have removed some and cleaned the IC's socket and the IC's pins.

The Power light off, the 5v micro bulb was faulty, replaced.

The keyboard had several problems;

The keyboard connector (socket) located on the computer motherboard side was faulty and consequently are missing the -12v for the keyboard encoder PCB.

The 3 TTL chips had been replaced on the keyboard encoder PCB but 2 x 74LS04 are erroneously soldered instead of 2 x 74LS00, the third TTL was correct but not working. Replaced all.

Now everything works reasonably well, unfortunately the bad keyboard has some problems, the internal slats are warped and tend out of their seat, as a result some keys do not work correctly.

I have tried to fix and clean, but the situation hasn't improved much.

Gallery of the repair:

After the usual boring PSU recap i have decided to add two displays to monitoring the main voltages (+5,+12) and the amperage.

The amperage displayed with the blue LEDs in the left display is the sum of all the voltages (+5,+12,-12).

I have also added three ventilation holes, i didn’t want to use any fans, i already have enough fans in the lab that are quite annoying.

Gallery:

Texas Instruments PHA 2037 Connector FIX

Defect:

• Black Screen but sounds works.

Replaced parts:

• 1 x 6 PIN DIN Male.

Gallery:

Texas Instruments TI-99/4A Repair #1

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x TMS9900NL CPU (U600)

Texas Instruments TI-99/4A Repair #2

Defect:

• Wave/Raster Lines.
• Garbage on Boot Screen.

Replaced parts:

• 1 x Inductor 2 -> 4.5 μH (L100)
• 2 x TMS4116-15 RAM

Texas Instruments TI-99/4A Repair #3

Defect:

• Garbage on Boot Screen.

Replaced parts:

• 1 x MOSTEK MK4116N RAM

Video amplifier installation for Composite Video output including installation of the two female RCAs on the case.

I also made a simple fix of the metal PAD of the RESET that no longer stayed in place and consequently fell off inside the shell.

Gallery:

You shouldn’t turn on an Amiga that has been off for about thirty years without first running the usual Recap, but also following this simple rule it is not said that everything works as expected.

After the Recap i have realized that the RGB / Composite and RF output were not working properly.

From the RGB output the BLUE color was missing while the composite video and consequently RF show only a black screen.

After various measurements i came to the conclusion that the VP-101 (U30) DAC had to be replaced.

Once the DAC was replaced, the RGB output started working perfectly again, while the Composite/RF video signal they still didn’t work.

The failed component for the Composite/RF video output is the Z222 delay line, bypassing the delay line on the pins of the same one i have a “decent” composite signal but it’s not good, unfortunately this component is not easy to find, it could be solved by performing a “hack” i.e. by installing a different RGB Encoder that doesn’t need the delay lines and with some modifications on the PCB.

The game is worth the candle ? when will we use the Composite/RF video output ? probably never.

Gallery of the repair:

Commodore 64 (ASSY 250466) Repair

Defect:

• Black Screen and then Black Screen :-D

Replaced parts:

• 1 x Power Switch
• 1 x PLA 906114 (U17)

Commodore 64 (ASSY 250407) Repair

Defect:

• Garbled Screen and then No Sound.

Replaced parts:

• 2 x MOS 7708 [74LS257] (U13/U25)
• 1 x MOS 7709 [74LS258] (U14)
• 1 x MOS 6581 (U18)

Commodore 64C (ASSY 250469 REV-A) Repair

Defect:

• Garbled Screen.

Replaced parts:

• 1 x 4066 (U21)

The return of the Hybrid Sid Player by xAD/Nightfall & Gianluca Renzi (RetroBit Lab)

Based on the Project and Hardware Schematic by Markus Gritsch released in the years 2011-2015 on the forum dangerousprototypes. Thanks Markus.

Changelog:

v1.22 – 6/2/2023

Note:

• From this release the new versions will be developed and tested on the v2 prototype PCB and no longer on the Breadboard prototype.

Added:

• Software implementation of the new audio Switcher.
• Added a new value (0: Nothing) to the DEFAULT_SID_SOCKET in the configuration file (config.ini).

  # Choose the default SID Socket on bootup (0: Nothing – 1:Socket #1 – 2:Socket #2) – default: 1
  DEFAULT_SID_SOCKET=1

• Added control via MCU of the power-up led. It might come in handy for future implementations.

Updated:

• Updated label on the oled display for the “sid switch” mode, now “sidSet” is written and not just “sid”
• Updated boot screen with the text “sorting files…” if the folder contains too many files (max 800).

Fixed:

• The encoder cannot be used for manual SID SWITCH mode in case the SID tune played is multitunes because the encoder is used to select the songs, so although the “sidset” option will be displayed on the display in this  specific case the selection of the sid socket will not working.
• Logic for the switch of the Socket SID with which to play the song and the consequent LED.
• Default SID Socket if nothing is specified in the config file (config.ini)
• Manual “sid switch” mode, the SID that was played with this mode would stop after 2 minutes and start over.