Between the early 1980's and late 1990's, the Motorola Two-Way Comms dealership/service center which I owned, attracted enough receiver repair work from department stores, (mostly Fisher "Studio Standard", and Marantz systems), that I began stocking a small inventory of 'Darlington Packs', which were fairly pricey. Many thanks for this trip down 'memory lane', and I'll be eagerly awaiting the second installment of this series.
Odd that all those fuse resistors were open. I can't imagine a scenario that would cause that. Typically fuse resistors will open when a semiconductor or cap shorts and draws excessive current. Great job Jordan in hunting this one down
I rebuilt a AU 717 purchased as non working. Every fuseistor was open. No other components were found bad. Replaced them and got it playing before recapping. It's pretty well known they just go bad for no apparent reason.
Nice video Jordan, well done! I have been working on a side project Sansui G-8700DB with Dolby FM and searching for the driver transistors for about 3 years. It was a total basket case as far as electrical shorted and burnt up parts, the owner said keep it, so I ordered all the output transistors, resistors and caps on the driver boards. I don't trust counterfeit transistors on the internet. 2SC2238B(O,Y) and 2SA968B(O,Y) I find that getting replacement semiconductors is the biggest road block to these old warriors having a go at life again. Last set of transistors I subbed in did not bias correctly on a Pioneer SX-636.
Great vid JP. I've worked in industrial electronics for my career and am getting into audio as a hobby. I sure do appreciate your vids and your narration skills as you troubleshoot. I'm learning a lot. Thank you.
That's one impressive looking beast, expensive in it's day. It's odd that the resistors were all ill on that pcb, not something I've seen. I blame a crap-acitor in the voltage regulator pcb. Really like the old designs, brushed aluminium facia. I bet the caps in my old pioneer SA706 Amp are ill, one day ill do it.
That’s definitely 💯 a receiver from my childhood. We never 👎 owned one ☝️, but these were 🔝 notch receivers. VU meters (6 of them), weighted flywheel tuning, and a lot of gadgetry on the front. This could make your local DJ jealous!! I liked 👍 the dial light 💡 these had. Your friend, Jeff.
I agree with you on the Vishay resistors. I ordered a couple 2W resistors for a Kenwood receiver and I thought they had sent me the wrong parts. I didn't see how they could work, but they did and they worked well : )
I believe there may be an error on board F 2638. Negative 45.5 vdc is indicated on the center tap of the 36-0-36 portion of the power transformer. More likely this minus 45.5 volts is present at the output of TR 602. Maybe?
You have to make them. There are ways to do this. Most importantly is the amp inside this is grounded through the cable at the top of the amp driver cards. If you modify it for pre-out/main-in Jacks the amp must always be grounded or it will oscillate out of existence.
@@JordanPier Ok, thanks. Right now I'm using Russound speaker to line adapters. They work, but they take up speaker connections. Anyway, I was hoping to free those up.
I worked on one like this but I couldn't figure out how the quadraphonic processor system works. I think it required a special turntable. I couldn't figure out how to test the quadraphonic synthesizer. Everything else worked
Cd-4 processor basically works like fm multiplexing for stereo, but a higher pilot frequency. I think its 25-28khz. The demodulated and matrixed pilot goes to the rear channels. The synth uses phasing information in the stereo signal along eith a logic processor to determine what parts of the stereo image gets sent to the rear and if its in or out of phase with the front channels
@@JordanPier I had to give it back to the customer. I couldn't figure it out. That's been awhile ago. I googled it and it read something about using a quadraphonic record recording that puts out a pilot frequency but the cartridge has to be high quality enough to pick up that frequency. The customer thought it would work with a regular turntable with a standard stereo record. I didn't have what it took to test it. I found dried out electrolytic capacitors in the synthesizer and it might be fixed
Unfortunately I do not have any spare parts for these sets Your best bet is to keep an eye out on eBay for parts machines or someone parting one out. The 7070-9090 share button covers and toggle switch covers and some knobs. The qrx-6001-9001 have the same QS decoder boards . The amplifier driver boards are the same as the 7070, 8080db, and 9090db Everything else is fairly unique to that machine.
Between the early 1980's and late 1990's, the Motorola Two-Way Comms dealership/service center which I owned, attracted enough receiver repair work from department stores, (mostly Fisher "Studio Standard", and Marantz systems), that I began stocking a small inventory of 'Darlington Packs', which were fairly pricey. Many thanks for this trip down 'memory lane', and I'll be eagerly awaiting the second installment of this series.
Odd that all those fuse resistors were open. I can't imagine a scenario that would cause that. Typically fuse resistors will open when a semiconductor or cap shorts and draws excessive current.
Great job Jordan in hunting this one down
I rebuilt a AU 717 purchased as non working. Every fuseistor was open. No other components were found bad. Replaced them and got it playing before recapping. It's pretty well known they just go bad for no apparent reason.
Nice video Jordan, well done!
I have been working on a side project Sansui G-8700DB with Dolby FM and searching for the driver transistors for about 3 years. It was a total basket case as far as electrical shorted and burnt up parts, the owner said keep it, so I ordered all the output transistors, resistors and caps on the driver boards. I don't trust counterfeit transistors on the internet. 2SC2238B(O,Y) and 2SA968B(O,Y)
I find that getting replacement semiconductors is the biggest road block to these old warriors having a go at life again. Last set of transistors I subbed in did not bias correctly on a Pioneer SX-636.
Great vid JP. I've worked in industrial electronics for my career and am getting into audio as a hobby. I sure do appreciate your vids and your narration skills as you troubleshoot. I'm learning a lot. Thank you.
Marantz !! 😂😂😂😂 Loved it JP...
Thanks for the tip about the 4-way connector being the ground source. I never saw any warnings on the AK forum concerning this.
That's one impressive looking beast, expensive in it's day.
It's odd that the resistors were all ill on that pcb, not something I've seen.
I blame a crap-acitor in the voltage regulator pcb.
Really like the old designs, brushed aluminium facia.
I bet the caps in my old pioneer SA706 Amp are ill, one day ill do it.
The new camera looks great!!
That’s definitely 💯 a receiver from my childhood. We never 👎 owned one ☝️, but these were 🔝 notch receivers. VU meters (6 of them), weighted flywheel tuning, and a lot of gadgetry on the front. This could make your local DJ jealous!! I liked 👍 the dial light 💡 these had. Your friend, Jeff.
I would imagine the worst part of being a tech is working on equipment that non-techs have already *tried* to fix.
I agree with you on the Vishay resistors. I ordered a couple 2W resistors for a Kenwood receiver and I thought they had sent me the wrong parts. I didn't see how they could work, but they did and they worked well : )
This is what I like Jordan
One of Sansui's monster receivers! I think it's two 9090db amps.
Nice I am repairing a Pioneer poweramp Bad electrolytics and cold solder joints and I replaced the soft start relay .
Looks terrifying.
This thing is a beast bet it’s too heavy that thing
I believe there may be an error on board F 2638. Negative 45.5 vdc is indicated on the center tap of the 36-0-36 portion of the power transformer. More likely this minus 45.5 volts is present at the output of TR 602. Maybe?
HI JORDAN I FOUND A Marantz Model 2275
Hi, how do you connect an external amp to this? I have one, though no pre Ins/outs found. Thanks.
You have to make them. There are ways to do this. Most importantly is the amp inside this is grounded through the cable at the top of the amp driver cards. If you modify it for pre-out/main-in Jacks the amp must always be grounded or it will oscillate out of existence.
@@JordanPier Ok, thanks. Right now I'm using Russound speaker to line adapters. They work, but they take up speaker connections. Anyway, I was hoping to free those up.
HI do you work on Marantz ? I have 2325 no sound to the speakers
Cant take in any more work right now. Im already backed up 6+mo
@@JordanPier Thanks
I worked on one like this but I couldn't figure out how the quadraphonic processor system works. I think it required a special turntable. I couldn't figure out how to test the quadraphonic synthesizer. Everything else worked
Cd-4 processor basically works like fm multiplexing for stereo, but a higher pilot frequency. I think its 25-28khz. The demodulated and matrixed pilot goes to the rear channels.
The synth uses phasing information in the stereo signal along eith a logic processor to determine what parts of the stereo image gets sent to the rear and if its in or out of phase with the front channels
@@JordanPier I had to give it back to the customer. I couldn't figure it out. That's been awhile ago. I googled it and it read something about using a quadraphonic record recording that puts out a pilot frequency but the cartridge has to be high quality enough to pick up that frequency. The customer thought it would work with a regular turntable with a standard stereo record. I didn't have what it took to test it. I found dried out electrolytic capacitors in the synthesizer and it might be fixed
Hey sir. Can you repair this unit and where you relocated at?/
Shop is located in la mesa, ca
Repairaudio dot com
Hi Jordan, I am looking for a part to restore my 9001. Can you help me?
Unfortunately I do not have any spare parts for these sets
Your best bet is to keep an eye out on eBay for parts machines or someone parting one out.
The 7070-9090 share button covers and toggle switch covers and some knobs.
The qrx-6001-9001 have the same QS decoder boards .
The amplifier driver boards are the same as the 7070, 8080db, and 9090db
Everything else is fairly unique to that machine.
@@JordanPier I actually just need the long one with 15x2 pins for the decoders. So hard to look for them. Thanks for replying