Technics 1700 mk2 auto return not working?
- Thread starter CDELON
- Start date
Register to hide this ad
Hey Cory,
There's a huge thread here: https://audiokarma.org/forums/index...hnics-sl-1600-1700-1800-owners-thread.532717/
Could be the infamous gear. The thread above will detail that as well as the audiokarma link for the service and other manuals.
Good luck!
Kevin
There's a huge thread here: https://audiokarma.org/forums/index...hnics-sl-1600-1700-1800-owners-thread.532717/
Could be the infamous gear. The thread above will detail that as well as the audiokarma link for the service and other manuals.
Good luck!
Kevin
CDELON
Active Member
paddypaws
Member
In case you missed my answer on the other thread:
have just done this auto arm returm repair on a Technics SL-1700 mk2 I recently bought. Unfortunately if the arm works when the stop button is pressed, like mine, its not mechanical and not an easy fix. If nothing works at all its probably just the drive belt on the separate arm motor. If some arm functions work but others don't like mine it'll be either dead CMOS chips on the logic part of the control board, or dead transistors or the chip on the arm driver board. Yours sounds same as mine, which was fixed by replacing two IC's - ic458 and ic459 on the logic part of the control board (TC4023 and TC4011) CMOS chips. The chips are available cheaply as new old stock. The chips all interact so it could be one of the others, there’s about six. This is what fixed the auto arm return on mine. The service manual has a good circuit description and schematic which can be downloaded for free. If you don't have good soldering skills, give it to someone that has. Good luck and please report back to what fixed it for you.
have just done this auto arm returm repair on a Technics SL-1700 mk2 I recently bought. Unfortunately if the arm works when the stop button is pressed, like mine, its not mechanical and not an easy fix. If nothing works at all its probably just the drive belt on the separate arm motor. If some arm functions work but others don't like mine it'll be either dead CMOS chips on the logic part of the control board, or dead transistors or the chip on the arm driver board. Yours sounds same as mine, which was fixed by replacing two IC's - ic458 and ic459 on the logic part of the control board (TC4023 and TC4011) CMOS chips. The chips are available cheaply as new old stock. The chips all interact so it could be one of the others, there’s about six. This is what fixed the auto arm return on mine. The service manual has a good circuit description and schematic which can be downloaded for free. If you don't have good soldering skills, give it to someone that has. Good luck and please report back to what fixed it for you.
CDELON
Active Member
Do you have a good source to buy the chips needed?
paddypaws
Member
No, I just used Ebay sellers with good feedback and fast delivery.
Hello, I have the following symptoms on mine: when the record ends, the tonearm lifts and the record continues to spin but the autoreturn does not work. When I press the STOP button, the tonearm returns and the record stops spinning but the cueing motor continues to run, then I press the cueing button and the tonearm down to the rest position. Do I have the same problem?
paddypaws
Member
Yes , It sounds like your arm is doing all the movements it requires, just not when it should. This would indicate a fault with the control board electronics. The arm control chips are easily obtained and cheap to buy being generic logic chips. Try following the fault finding flow chart in the service manual to guide you to the right chip that's faulty. It's not a big deal to replace the lot if it comes to it. ( The chips all interact so it can be difficult to assess which one has gone.)
Last edited:
paddypaws
Member
Maybe try the two I replaced first, your fault does sound the same as what I had with mine.
Thunderbox
Super Member
It has nothin to do with the electronics. The motor does not directly move the lift. It is a mechanical contact with a disc that actually lifts the arm rest. Check to make sure your arm lift is easy to move upwards manually.
paddypaws
Member
If you read the post above he's already checked the arm does all the movements correctly using the stop button. It's everything to do with the electronics.
Thunderbox
Super Member
So the one I fixed last week had a different mechanism for lifting the arm and returning. Not
paddypaws
Member
There's no varieties of arm motor drive mechanism on a 1700mk2. You must've been looking at the SL-1700 (mk1) or some other model, the 1700mk2 is a completely different turntable, in every way to the mk1. The only other one in the range which is a bit similar is the SL- 1600mk2 which has the same motor driven arm mechanism but completely different arm electronics with a microcontroller, it's the fully automatic version.
Last edited:
I think maybe you're confusing with a MK1 - unless I'm misunderstanding your verbiage, the 1700/1710 MKII is electronic queuing.
Thunderbox
Super Member
It is electric but not electronically operated. The arm is lifted by a circular disc with a raised part and a lower part. As it turns it lifts the arm or lowers it.
paddypaws
Member
Don't know what your looking at but it's not an SL-1700mk2 or 1710mk2. Or are you just trolling. The arm is electronically operated. That's what this thread is about. There's a whole control board, and an arm board with a whole bunch of integrated circuits just dedicated to controlling the arm movement via transistors that drive the electric motor which moves a clutch, then a gear and a roller that moves the cam on the arm. The vast majority of the service manual is dedicated to detailing how the electronics are driving the arm.
Last edited:
Thunderbox
Super Member
Before you go any further I just had one all apart week and a half ago. Have you ever had one apart. The only part that works by electric is the arm return. The little motor runs a belt and the motor turns a worm gear which will only allow the arm to move when and if the arm is lifted, preventing an obviously damaging scrape across the record.. That is the soul purpose of the ICs in the TT. Believe me I know what I am talking about and yes it is Technics SL-1700 MKII. The electric motor is controlled by the ICs in the TT but if the motor runs when you push the lift button it is not the electronics. Check to see if the arm lift can move up freely when a small screwdriver is placed between the under part of the arm rest and the body of the TT. If it is not nice and loose then the disc I was talking about can not move far enough to release the return mechanism and it isn't electronic. This problem occurs when the lubricant in the lift ram gets old and hard from not being used for some time.
Last edited:
paddypaws
Member
Yes, I own 1700mk2 and have spent many hours on the electronics. You are wrong. The cueing or 'lift button' only grounds pin1 of IC 457 which outputs to IC 460 which is the flip flop for the control of motor direction. It's all part of the electronic arm control.
In any case the poster above asking the questions, (picturesd) asked about the auto return not working, not the cueing/lift which he has said works. He has already stated the arm movement all works - up and down and the stop/return button works and returns the arm, just not automatically. Please read the thread properly.
Last edited:
twiiii
Lunatic Member
I learned a long time ago either by owning automatics or full changers used as automatics that they are always going to give you problems much sooner than a pure manual table. Simple motor driven tables using a puck or a belt are are going to last longer than DD dive or electronically controlled belt driven tables. We had one bench technician and all he did was basically repair Automatic and changer type turn tables. Yes he installed SME and Ortofon arms on basic turntables and mounted cartridges. He checked stylus assemblies and cartridge alignment and replace cartridges all the time too. He was a busy boy. It seemed to me that his 8 X 8
stack of shelves was always full of turntables to be repaired or ready for pick up.
I've been very lucky as my 50+ year old Thorens TD 125 hasn't given me any issues until recently. The problem has been the lack of quality control by Thorens in making drive belts. MY friends at Audio Classics found another belt made by some one else that has worked perfectly for the last couple of years. The TT comes up to speed more quickly and the speed stabilizes much faster and more consistently from a cold start. Some times it would take an hour for the table to settle down with a Thorens belt.
The 5 year old VPI/Levinson 515B Dragon TT with the Fat Boy Gimbaled arm hasn't given me one issue after I figured out not only does the TT have to be level but the separate motor box drive motor pulley has to be level. No matter if the motor box is level or not.
stack of shelves was always full of turntables to be repaired or ready for pick up.
I've been very lucky as my 50+ year old Thorens TD 125 hasn't given me any issues until recently. The problem has been the lack of quality control by Thorens in making drive belts. MY friends at Audio Classics found another belt made by some one else that has worked perfectly for the last couple of years. The TT comes up to speed more quickly and the speed stabilizes much faster and more consistently from a cold start. Some times it would take an hour for the table to settle down with a Thorens belt.
The 5 year old VPI/Levinson 515B Dragon TT with the Fat Boy Gimbaled arm hasn't given me one issue after I figured out not only does the TT have to be level but the separate motor box drive motor pulley has to be level. No matter if the motor box is level or not.
