Digital Multimeter 178
Keithley Instruments Inc.; Cleveland (OH)
- Country
- United States of America (USA)
- Manufacturer / Brand
- Keithley Instruments Inc.; Cleveland (OH)
- Year
- 1978 ?
- Category
- Service- or Lab Equipment
- Radiomuseum.org ID
- 190744
Publicidad Keithley
Click on the schematic thumbnail to request the schematic as a free document.
- Number of Transistors
- Semiconductors present.
- Semiconductors
- Wave bands
- - without
- Power type and voltage
- Dry Batteries
- Loudspeaker
- - - No sound reproduction output.
- Material
- Plastics (no bakelite or catalin)
- from Radiomuseum.org
- Model: Digital Multimeter 178 - Keithley Instruments Inc.;
- Shape
- Portable set > 8 inch (also usable without mains)
- Notes
- 4 1/2 digitos, AC/DC 0-1000V, 0-20 MOhm.
- Price in first year of sale
- 29,900.00 Ptas
- Mentioned in
- Mundo Electronico Nº 81 enero de 1979
- Author
- Model page created by Alberto Sanna-Alonso. See "Data change" for further contributors.
- Other Models
-
Here you find 38 models, 33 with images and 16 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Keithley Instruments Inc.; Cleveland (OH)
Forum contributions about this model: Keithley Instruments: Digital Multimeter 178
Threads: 1 | Posts: 1
En el Service Manual del Modelo 178 de Keithley existen dos transistores que el fabricante no ha identificado, los Q104 y Q105, N-Channel JFET.
En el circuito real estos dos transistores están pintados en blanco para ocultar su denominación.
En mi Keithley modelo 178 he podido limpiar la pintura con mucho cuidado y he podido identificar los dos transistores.
Tanto Q104 como Q105 son el tipo PN4392 de National Semiconductor.
Im Servicehandbuch des Keithley Modell 178 sind zwei Transistoren aufgeführt, die der Hersteller nicht identifiziert hat: Q104 und Q105, N-Kanal-JFETs.
In der Schaltung sind diese beiden Transistoren weiß lackiert, um ihre Bezeichnungen zu verbergen.
Bei meinem Keithley Modell 178 konnte ich die Lackierung sorgfältig reinigen und die beiden Transistoren identifizieren.
Sowohl Q104 als auch Q105 sind vom Typ PN4392 von National Semiconductor.
In the Keithley Model 178 Service Manual, there are two transistors that the manufacturer has not identified: Q104 and Q105, N-Channel JFETs.
In the actual circuit, these two transistors are painted white to hide their designations.
On my Keithley Model 178, I was able to carefully clean the paint and identify the two transistors.
Both Q104 and Q105 are National Semiconductor type PN4392.
Vicente Moncholi-Cebrian, 06.May.25