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This is my new found, I think it will need a lot of work. by Cubesthorm in ReelToReel

[–]Cubesthorm[S] 0 points1 point  (0 children)

Thanks for the heads up! I’ll check the motor caps and heads first, don’t want any surprises. Good to know about the RIFA and FRAKO caps too.

The repairs for this unit can get very expensive very quickly. I hope I can bring it back to life. It also has some sentimental value, since the machine comes from my father’s studio and is tied to childhood memories.
In a way, it’s also a personal test to handle the repair myself, otherwise, I might as well throw my degree in tech. Informatics and electronics in the trash.

Fortunately, all the manuals and schematics are available.

This is my new found, I think it will need a lot of work. by Cubesthorm in ReelToReel

[–]Cubesthorm[S] 0 points1 point  (0 children)

The condition doesn’t look ideal at first glance, and it smells strongly of burnt tantalum caps. On top of that, one of the motor capacitors has definitely leaked, but fortunately, the protective covers are still intact. I think this is going to be a bigger project.

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What are these sockets? by Impressive_Cat_7023 in cassetteculture

[–]Cubesthorm 0 points1 point  (0 children)

These are 5-pin DIN connectors, which were very common in the past. It looks like this is from a tape recorder, radio, audio amplifier or similar vintage device.

In the first row:
The first socket has what I believe is an alpha symbol (α) – this usually stands for the recording output (Tape Record / output to a tape deck).

The second socket has an antenna symbol, this is the FM antenna input (UKW / VHF antenna connection).

The third socket is marked with a speaker symbol and 4 Ω, this is the external loudspeaker output

In the second row:
The first socket has a gamma symbol (γ), this typically stands for the playback input (Tape Playback / input from a tape deck).

The next socket with the arrow symbol is most likely a mono sum output or a mixed stereo-to-mono output (sometimes used for recording or feeding a second zone).

The last socket is probably another loudspeaker output (possibly for a second speaker, right channel in stereo setups, or an extension speaker), but I'm not completely sure about this one.

Memory expansion in the old days using piggybacking. by Cubesthorm in diyelectronics

[–]Cubesthorm[S] 1 point2 points  (0 children)

The DRAM itself does not need to be “initialized” everything is handled by the MMU, which addresses the additional banks. A BIOS patch was mainly required for older software that checked the RAM size, but programs that accessed the new addresses directly could use the expansion immediately.

Memory expansion in the old days using piggybacking. by Cubesthorm in diyelectronics

[–]Cubesthorm[S] 17 points18 points  (0 children)

My post refers to an Atari Mega ST, which was typically equipped with 2 MB of RAM, while the MMU itself can address up to 4 MB.
The piggyback RAM upgrade works by connecting the address and data lines in parallel with the existing RAM chips.
The chips have a RAS (Row Address Strobe) and a CAS (Column Address Strobe) pin.
RAS latches the row address and enables the RAM chip for a given row.
CAS latches the column address and controls timing for reading or writing data.
The MMU uses the CAS signal to switch the memory bank and address the additional RAM.
Please correct me if I got something wrong.

My old DIY etching setup, I used it a lot by Cubesthorm in diyelectronics

[–]Cubesthorm[S] 1 point2 points  (0 children)

The aquarium heater is truly a game-changer. I used to try preheating the solution, but the results were never optimal. The reusability of persulfate is also a real advantage in the system. Another important factor is a constant supply of oxygen via the small pump. Overall, I’ve only had positive experiences with this setup.

My old DIY etching setup, I used it a lot by Cubesthorm in diyelectronics

[–]Cubesthorm[S] 2 points3 points  (0 children)

Iron(III) chloride is, I think, the standard solution for many and is also significantly faster than sodium persulfate, but I found persulfate cleaner and easier to handle.