TASCAM 85 Series Reel-to-Reel Tape Deck Repair Guide

Series Overview

The TASCAM 85 Series represents professional-grade reel-to-reel tape decks designed for studio use. These models are known for their robust construction, excellent audio quality, and advanced features.

Common Issues and Solutions

Transport Mechanism Problems

The TASCAM 85 Series features a complex transport system that can develop issues:

• Brake system issues: Worn brake bands can cause improper tension control
• Pinch roller deterioration: Hardened rubber causes tape handling problems
• Motor capacitor failure: Causes slow starting or uneven tape speed
• Tension sensor problems: Dirty or misaligned sensors affect tape handling

Electronic Issues

Common electrical problems include:

• Capacitor failure: Electrolytic capacitors dry out, causing various issues
• Relay contact problems: Oxidized contacts cause intermittent operation
• Power supply issues: Failed regulators or diodes cause incorrect voltages
• Potentiometer noise: Dirty pots cause crackling in audio controls

Capacitor Replacement Guide

The following capacitors should be replaced in any comprehensive restoration:

Critical Components to Check/Replace

Component	Reference	Location	Notes
Voltage Regulators	IC101, IC102	Power Supply	Check for proper output voltages
Relays	RLY101-RLY104	Control Board	Clean or replace oxidized contacts
Brake Bands	N/A	Transport	Replace if worn or glazed
Pinch Roller	N/A	Transport	Replace if hardened or cracked
Tension Sensors	N/A	Transport	Clean and adjust for proper operation

Mechanical Maintenance Procedure

1. Disconnect power and remove covers
2. Carefully clean the transport mechanism with isopropyl alcohol
3. Inspect and replace worn brake bands if necessary
4. Remove old hardened lubricant from all moving parts
5. Apply fresh lubricant to appropriate areas:
   • Capstan bearing: Light machine oil
   • Guide rods: Light grease
   • Levers and pivots: Light machine oil
6. Clean and inspect the pinch roller; replace if hardened or cracked
7. Check and adjust tape tension as needed
8. Clean all switches and potentiometers with contact cleaner
9. Clean tension sensors with isopropyl alcohol

Calibration Procedure

After capacitor replacement, these calibrations are essential:

• Set playback level and EQ using MRL calibration tape
• Adjust record level and bias for each tape type
• Check and adjust tape tension across all modes
• Verify tape speed accuracy at all speed settings
• Adjust head azimuth for proper high-frequency response
• Calibrate reproduce and record electronics for all channels
• Set proper brake tension for smooth operation

Additional Tips

• Use high-quality, low-ESR capacitors for longer life
• Document all adjustments before making changes
• Check all resistors near replaced components; they may have drifted in value
• Clean the record/playback switches thoroughly as they often cause noise
• Allow the unit to warm up for 30 minutes before making final adjustments
• Consider replacing relay contacts if they show signs of pitting or oxidation