Retro Resto #1 | Vintage ASMR | 1970s R2R Restoration | Sanyo MR-115 Mono | 1/4" | 3.75-ips

In this video, I repair and test a Sanyo MR-115-C reel-to-reel tape recorder circa 1972.

Purchased from Ebay with original box and accessories (mic, cables...), listed as "For Spares Only".

It actually was functioning when it arrived, and was in generally good condition overall, some minor problems like dried up lubricants and some slightly worn out electronic components, but nothing unexpected for a 50+ year old deck that has probably never had any servicing since the 70s.

I disassemble the deck to access all moving parts and the electronics, clean out the old congealed grease, re-lubricate, and replace all 12 electrolytic capacitors in the power supply and audio electronics circuit.

Volume and Tone controls are also cleaned and returned to full working order with the aid of some cotton buds and DeOxit D100.

The Erase and Record heads are fully cleaned with isopropyl alcohol (IPA) and demagnetised with a Han-D-Mag demagnetiser.

The pinch roller, rubber idler tyres and belts only needed cleaning to restore them to working condition.

After repairing, cleaning and re-assembly, the deck has greatly improved sound "quality", with a noticeable increase in the high frequencies and lower distortion.

The basic design of this deck, and it's 2-head mono format make it impossible to properly calibrate in the same way a higher quality deck would be done, added to this is the almost total lack of adjustable trimmers on the PCB, with a single 10k trim-pot on the bias circuit being the only adjustment possible.

A bit of "trial-&-error" was required to get it recording at an acceptable level, and the end result is a half decent HF response, plus a significant reduction in harmonic distortion, and slightly lower wow/flutter, but the signal/noise ratio is still incredibly high, with vast amounts of tape hiss present when in playback.

The electronic circuit itself appears to be a lot quieter after replacing all the electrolytic capacitors, and the volume now works all the way up to 100% without distorting or crackling.

While this was never a great sounding machine, it's mainly intended to do basic speech recording and maybe record some tunes from the radio, it's lo-fi sound and audible artifacts are somewhat sought after by artists who want to add some old-school tape grunge to their recordings without having to spend $1000s on a higher-end machine. Hence the fact that I haven't gone to great lengths to reduce the s/n ratio or w/f numbers, it's flaws are what makes it's appealing.

The tape type used is new LPR35 from Recording The Masters (RTM), and while higher grade tape (LPR90) is available, the LPR35 is the best match for this particular deck.

I will be following up this video with another that demonstrates the original Sanyo HM-8 dynamic microphone, and compares it to a Shure SM57 dynamic to give a good contrast between low quality and studio grade mics.

The music used in this video is all original material by me, and is either already available, or will soon be available from my official bandcamp store:
https://dogwooddags.bandcamp.com

I don't do restoration for a job, it's a hobby/necessity, but if you'd like me to restore your vintage audio gear, I am happy to accept it as a donation, I won't return it, but I will make a video of it you can watch.

Contact me via: [email protected] to see if I am willing/able to take your gear.

WARNING! THESE VIDEOS ARE FOR ENTERTAINMENT ONLY. DO NOT ATTEMPT TO WORK ON HIGH VOLTAGE EQUIPMENT UNLESS YOU ARE FULLY QUALIFIED AND COMPETENT. DON'T BECOME A DEAD COPYCAT!

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