Dynaco MKIII MK-III MK-IV Complete Restoration Service

Description

We also have a wide selection of power tubes suitable for this amplifier.
This listing covers a complete restoration for your Dynaco MK III or MK IV amplifier, along with a complete power supply rebuild. The price does not include return shipping or packing if a new box is required.
If you have just purchased an amplifier, have it sent to us for a complete checkout and Power Supply Rebuild. Here is what the service covers, there are (2) inspection service groups included in the price:
Inspection Service Part 1
Visual inspection of the top and bottom of amplifier, bottom cover off. Look for burnt resistors, leaking capacitors, blown fuses,   defective rectifier diode and other defective components etc.
Power the amplifier up in slow stages, with a Variac, to avoid shocking older electrolytic in the power supply, and to allow them to reform.
Check all power supply voltages at the specified operating line voltage, according to manufacturer specifications
Check all resistances at tube pins (when specified by manufacturer)
Check All Electrolytic Capacitors for ESR (Quality) using an 88A Capacitor Analyzer, leakage and value
Check audio coupling capacitors for leakage, quality and value
Check all vacuum tubes on an Amplitrex AT-1000 computer controlled tester.
Check bias current for all output tubes to ensure it is within normal operating range
Check condition of input jacks and output terminal strips
Check condition of switches and potentiometers
Check for signal throughput and condition of output transformers - inject  1Khz signal at each channel input and check for output at each channel's speaker terminals (loaded at 8 ohms). Check output transformers for continuity and winding shorts.
If anything above is found  NOT correctable by simple means (no significant additional labor and no parts), issue Initial Report to customer by email or call.  If customer decides not to move forward, only a .00 bench fee + return shipping is charged.
At this point the Power Supply is completely rebuilt using Our MK-III Deluxe refurbish kit (sold separately for you do it yourself types in our Ebay Store).  We then replace the  filter cap with our German o made 30/20/20/20  550V capacitor can. This can is the same height as the original. Bass response, impact and palpability are astonishing.  We replace the selenium (or old) silicon rectifier with a silicon diode 1A @1000V PIV. We replace the bias capacitors with  high grade high temperature 47uf /250V electrolytics. We then determine and select series a resistor to set the bias to exactly factory specs. Everything is neatly wired. We then re-check all power supply and  operating voltages.
In addition, all audio path capacitors,Illinois Capacitor MPW or Mallory 150M polypropylene types, 600 V rated.
The Matched pairs of 100K and 47K resistors are replaced, as well as the 2 feedback loop capacitors. These are replaced with high quality Silver Mica types.
We also replace the GZ34 rectifier with a Mullard Re-issue.
See our Deluxe Restoration Service which includes new circuit boards (either for 7199 or 6GH8 tubes and all tubes.
Inspection Service Part II
Re-check Power Supply and operating voltages
Clean tube sockets and switches with Deoxit 5, re-tension tube socket pins as required
Clean potentiometers as required
Measure Output Power into 8 Ohm Loads
Measure sensitivity for full power output
Measure Channel Balance
Measure distortion (THD) @1Khz, half and full power output
Measure frequency response (20Hz,40hz, 100h,250Hz,500Hz,1Khz,5Khz,10Khz,15Khz,20Khz,25Khz 30Khz)
System listening test - Assess quality of sound
Light cleaning of chassis
Issue Final Report to customer by Email or Call
If we find anything seriously wrong in the Inspection Service Part 1, we will call you or email you an initial report, so you can decide if you want to repair things or not and upgrade the power supply. If you decide NOT to go ahead, or your amplifier cannot be repaired, you only pay a 90.00 bench fee and return shipping charges.
After completion of Inspection Service Part II, we will provide you final a written report, by email (or USPS if desired), of you amplifier's health. A copy will be returned with your amplifier. This report will list recommendations for improvements as well as potential problems found, with costs for possible repair or upgrade. No further work will be performed without your consent. All you pay at this point is the listed price plus return shipping.
This service does not include return shipping or any additional costs for labor and parts/tubes to repair defects found above and beyond those stated int he listing. These will be billed separately should you agree to go forward.
Our pricing is introductory pricing, so take advantage of the low pricing now, and have your amplifier checked thoroughly. Please double box it and ship it to us insured. We will return it to you in your packaging. If your packaging is damaged, there will be a nominal charge for packing materials, so make sure you packing is rugged..
We at CTech electronics have been in the electronics industry for over 49 years, and we are also audiophiles. We stand behind our products and services. You equipment is treated as if it were our own.
Visit our Ebay Store for a large selection of parts, tubes and services. We are a full service company.