Simpson 260 — Vol 6: Cheatsheet (laminate)

6.1 Purpose & How to Use This Sheet

This volume is a synthesis, not a source — it distills Vols 2–5 into lookup tables for the bench. Every row that states a fact carries a “detail:” pointer back to the volume and section where the full explanation, the caveats, and the confidence-tagged sourcing live. If a number here disagrees with your memory of Vol 2–5, the earlier volume wins — this sheet is compressed for speed, not for nuance.

Laminate rule of thumb: if you only keep one section taped inside the lid, make it §14 (Safety DON’Ts) and §5 (Series-ID Quick Key) — those are the two most likely to prevent damage to the meter or to you.

Note — Zero photos in this volume by design. It’s meant to survive a laser printer and a lamination pouch; halftones don’t. For visual ID references (dial photos, panel photos, case photos) see Vol 2.

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6.2 Why Reach for This Meter (30-second version)

Table 1 — 1. Why Reach for This Meter (30-second version)

Analog trait	Why it matters on the bench	Detail
Needle shows rate + direction of change	Peaking, nulling, dip-finding (alignment, bridge nulls, tuning) — trivial on a swinging needle, painful watching jumping DMM digits	Vol 1
Mechanical inertia smooths a noisy signal	A flickering/fluctuating reading settles to a mean instead of strobing through random digits	Vol 1
Ohms ranges drive a known current	Test diodes both directions, transistor B-E/B-C junctions, watch a cap “kick” and discharge — real hands-on component testing a DMM’s near-zero-drive ohms function can’t do the same way	Vol 1, Vol 3 §6
No warm-up, no battery for V/I ranges	Works instantly, works when a DMM’s battery is dead	Vol 1
Lower input impedance (20 kΩ/V)	Actually rejects ghost/phantom voltages that fool a 10 MΩ DMM — loads out induced/leakage voltage so a real source shows real current draw	Vol 1
Rugged, RFI-tolerant, sunlight-readable	Field-serviceable characteristics a digital display doesn’t share	Vol 1

Note — This is not “vs DMM, which wins” — it’s “which tool for which node.” For high-impedance nodes (grids, screens, AVC lines) the 260’s 20 kΩ/V loading is a liability, not an asset — reach for the B&K 375 VTVM or Simpson 311-2 VTVM instead. Detail: Vol 1.

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6.3 Headline Specs

Table 2 — 2. Headline Specs

Parameter	Value	Detail
Movement	D’Arsonval moving-coil, 50 µA full scale, 250 mV drop at FS	Vol 3 §1
DC sensitivity	20,000 Ω/V	Vol 3 §3
AC sensitivity	5,000 Ω/V (average-responding, sine-RMS calibrated, 100 Hz reference)	Vol 3 §5
DC volts accuracy	2% of full scale	Vol 3 §3
AC volts accuracy	3% of full scale	Vol 3 §5
DC current accuracy	2% of full scale (1.5% on the 50 µA range)	Vol 3 §4
Ohms center-scale (R×1 / R×100 / R×10,000)	12 Ω / 1,200 Ω / 120,000 Ω	Vol 3 §6
Rated circuit-to-ground voltage	1000 V AC/DC max (per ANSI C39.5)	Vol 4 §9
Case (Series 8/8P)	5½″ × 7″ × 3″, 3 lb, heavy-wall phenolic	Vol 2 §5
Calibrated position	Horizontal — accuracy is specified with the meter lying flat	Vol 3 §1
Movement suspension (Series 8)	Taut band, standard	Vol 2 §3
Dial (Series 8)	Mirror-backed, tri-colored, standard (why “8” has no “M”)	Vol 2 §3
Movement protection (base 8 / 8P)	Diode network (both) + resettable relay, ~3× FS trip (8P only)	Vol 2 §4
Current status	Still in production — 260-8 / 260-8P / 260-8MCS / 260-9S / 260-9SP	Vol 2 §7

Note — “20,000 Ω/V” is a derived number, not a knob setting: the multiplier bank plus the movement total 100 MΩ from the “5000 V.” jack to COMMON−, and 100,000,000 Ω ÷ 5000 V = 20,000 Ω/V. Detail: Vol 3 §3.

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6.4 Full Range Set — Series 8 / 8P

Table 3 — 3. Full Range Set — Series 8 / 8P

Function	Ranges	Accuracy	Notes	Detail
DC Volts	0-1-2.5-10-25-50-250-500-1000 V	2% FS	20,000 Ω/V; 5000 V via external HV probe only — not a switch position	Vol 3 §3, Vol 4 §8
DC Millivolts	0-250 mV	2% FS	shares the 20,000 Ω/V ladder	Vol 3 §3
AC Volts	0-2.5-10-25-50-250-500-1000 V	3% FS	5,000 Ω/V; average-responding, sine-RMS calibrated	Vol 3 §5
Output (AC)	0-2.5-10-25-50-250	—	AC component only; blocks up to 350 VDC	Vol 3 §7
DC Microamperes	0–50 µA	1.5% FS	the base movement current; 250 mV drop	Vol 3 §4
DC Milliamperes	0-1-10-100-500 mA	2% FS	drop ≈250/255/300/500 mV across the ranges	Vol 3 §4
DC Amperes	0–10 A	2% FS	≈255 mV drop; shunt wired straight to the ±10 A jacks — NOT fused	Vol 3 §4, §12 below
Decibels	−20…+50 dB across 5 ranges	—	0 dB = 1 mW into 600 Ω	Vol 3 §7
Resistance R×1	0–2,000 Ω	2.5° arc	1.5 V open-circuit, 125 mA short-circuit	Vol 3 §6
Resistance R×100	0–200,000 Ω	2° arc	1.5 V open-circuit, 1.25 mA short-circuit	Vol 3 §6
Resistance R×10,000	0–20 MΩ	2° arc	9 V open-circuit, 75 µA short-circuit	Vol 3 §6

Note — The 0–25 V AC/DC range and the mirrored dial are the two features that specifically mark a Series 8 (new vs. Series 7). Detail: Vol 2 §2, §4.

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6.5 Battery Complement by Series

Table 4 — 4. Battery Complement by Series

Series	Low-ohms battery (R×1 / R×100)	High-ohms battery (R×10,000)	Notes	Detail
Original 260 (Series 1)	one 1.5 V “C” cell, soldered in	two 3 V cells (Burgess 422 / Eveready 750 or 905), ≈6 V total, soldered in	no back-cover access — full teardown to service	Vol 2 §1, §2
Series 2–5	one 1.5 V “D” cell	~6 V pack (commonly 4× AA in series)	Series-5 wording is ambiguous on whether 4×AA is original or a common workaround — [UNCERTAIN]	Vol 2 §2
Series 6 / 6P / 7 / 7P / 8 / 8P	one 1.5 V “D” cell, NEDA 13F	one 9 V battery, NEDA 1604 / 1604A (use alkaline)	Series 6 is the first to standardize the D + 9 V combo; on P models the 9 V also powers the overload relay	Vol 2 §2, Vol 5 §1

⚠ Danger — Do not use “15 V” or “30 V” for any 260 high-ohms battery — those figures are unverified for this instrument and likely a mix-up with a different Simpson/other-brand meter. The Series 6-and-later high-ohms cell is 9 V, full stop. Detail: Vol 2 §2.

Battery-holder mechanics (Series 6/8, the ones you’ll actually service):

Table 5 — Battery-holder mechanics (Series 6/8, the ones you'll actually service):

Cell	Holder	Failure mode
1.5 V D cell	Retained by two spring-steel clips that are themselves the contacts	Leaked electrolyte corrodes the clips → intermittent or dead R×1/R×100
9 V	Spring clip plus a separate polarized snap connector	Corroded snap → dead R×10,000 and, on P models, a relay that won’t hold reset

Detail: Vol 5 §1 (this is Jeff’s actual 6P repair — full before/after case study there).

Coarse era tell: soldered 3 V + C-cell → original; D + 4×AA → Series 2–5; D cell + 9 V → Series 6-on. Detail: Vol 2 §6.

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6.6 Series-ID Quick Key

Ordered fastest-tell to finest. Work top to bottom; stop as soon as you’re confident.

Table 6 — 5. Series-ID Quick Key

#	Tell	Reading	Detail
1	Dial text	From Series 2A on, the series is usually printed on the dial (“260 SERIES 6P”). The original has no series marking and shows patent 2,051,399 instead.	Vol 2 §6
2	Jacks	Pin-type recessed jacks → original or Series 2 (pre-1959). Banana jacks → Series 3 on. Reverse-banana safety jacks → Series 7 on.	Vol 2 §6
3	Handle & case	Leather handle + silk-screened face → original. Molded black case + engraved lettering + Adjust-A-Vue tilt handle → Series 2A on.	Vol 2 §5, §6
4	Rubber corner feet	Present → Series 6 on (raised bumps with no rubber → Series 5 and earlier; AFP-1 military has rubber feet screwed onto the bumps).	Vol 2 §6
5	Battery/fuse door	A separate small battery/fuse door → Series 6 on. Full back must come off to reach batteries → Series 5 and earlier.	Vol 2 §6
6	Front reset button	Present, left of the Simpson logo → a “P” model (5P/6P/7P/8P/9SP). Absent → non-P.	Vol 2 §4, §6
7	Mirrored dial	Present → 4M/5M/6M/7M, or any Series 8/9 (mirror is standard there). Absent → base Series 1–7 non-M.	Vol 2 §3, §6
8	Transit / OFF-transit switch position	”Transit” position appears from Series 6. An “OFF/transit” position on the AC/DC switch is a Series 7+ tell.	Vol 2 §6
9	Pot date codes (Series 3+)	Internal CTS pots carry EIA code 137 + a year/week (e.g. 137 72 56 = CTS, 1972, week 56) — narrows to a year within a series. [LIKELY, forum-sourced]	Vol 2 §6
10	Battery type	Soldered 3 V + C cell → original. D + 4×AA → Series 2–5. D + 9 V (NEDA 1604A) → Series 6 on.	Vol 2 §6, §3 above

⚠ Danger — the two traps a hostile reviewer will check for:

• Taut band did NOT start on Series 8. It debuts on the 5M (~1969), becomes standard at Series 6 (~1973). Series 8 is taut-band because everything from Series 6 on is taut-band — not because Series 8 invented it. Detail: Vol 2 §3.
• The 4M is mirror-but-not-taut-band — mirror (4M, ~1963–66) and taut band (5M, ~1969) landed one series apart. Don’t let “mirrored dial” alone imply taut-band suspension on anything before Series 6. Detail: Vol 2 §3.

6.6.1 Decision tree

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6.7 Per-Series Comparison — Condensed

The full per-series walk with dates, sourcing, and confidence tags is Vol 2 — this is the lookup version.

Table 7 — 6. Per-Series Comparison — Condensed

Series	Approx. years	Key changes from prior	Movement	Overload protection	Detail
Original / “Series 1”	patent 1936; sold ~1939–1946, radiomuseum span ~1939–1951 [UNCERTAIN]	baseline; bakelite back + leather handle; silk-screen; pin jacks; soldered-in batteries	Pivot-and-jewel	None	Vol 2 §1
Series 2 / 2A	1940s–1950s; manuals 1956 [LIKELY]	Engraved lettering; molded black case; Adjust-A-Vue handle; “Series” first printed on 2A	Pivot-and-jewel	None	Vol 2 §2
Series 3 / 3A	~1958–1959 [CONFIRMED ~1959]	Banana-jack leads; PCB introduced; rear adapter lock; batteries serviceable from a back cover; 3A adds self-shielding spring-loaded jewels	Pivot-and-jewel (self-shielding from 3A)	None	Vol 2 §2
Series 4 / 4M	~1963–1966 [LIKELY]	Improved PCB with calibration trimpots; 4M = first mirrored dial, still NO taut band	Pivot-and-jewel, self-shielding	None	Vol 2 §2, §3
Series 5 / 5M / 5P	~1968–1969 [CONFIRMED late-1960s]	PCBs withstand higher voltage; 5M = first taut band; 5P = first overload protection (transistorized relay + reset button)	5/5P pivot-jewel; 5M taut band (first)	5P only: transistorized relay + reset	Vol 2 §2, §3, §4
Series 6 / 6M / 6P / 6XL	~1973 [CONFIRMED ~1973 launch]	Taut band now standard; transit position; combined 1000 V jack; +1 V DC jack; 0–10 DC scale; 3 Amp-Clamp scales; separate battery/fuse door; rubber feet; D + 9 V battery combo standardized	Taut band (standard)	Base 6: fuses. 6P: fuses + resettable relay + reset button (Jeff’s unit)	Vol 2 §2, §4
Series 7 / 7M / 7P / 7PRT	”~1975–1985” vs radiomuseum “1980–2000 ??” [UNCERTAIN, both recorded]	First OFF/transit position; reverse-banana safety jacks; “1000 V to ground” printed; meter window resized	Taut band (7M mirrored)	Base 7: fused. 7P: fused + resettable	Vol 2 §2
Series 8 / 8P / 8Xi / 8RT	~1990s–present; launch ~mid-1990s [LIKELY]	Mirror + taut band both standard → “M” suffix dropped; tri-colored mirrored dial; self-shielding taut-band movement (Jeff’s unit)	Taut band (standard)	Base 8: diode network. 8P: diode network + resettable relay + 2 fuses + reset + buzzer	Vol 2 §2, §4
Series 9 / 9S / 9SP	~2006–present [CONFIRMED current]	Safety-rated redesign: EN61010-1, 600 V CAT III; lighter (~2.5 lb)	Taut band	9S base + 9SP protected variant	Vol 2 §2

Note — “Series 1” is a collector convention — Simpson never printed a series number on the original; it carried no series marking at all until Series 2A. Cite it as the original 260, not a factory “Series 1.” Detail: Vol 2 §2.

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6.8 Case & Military Variant Quick ID

Table 8 — 7. Case & Military Variant Quick ID

Variant	Identifying features	Notes	Detail
Standard case (2A on)	Molded black case, engraved lettering, Adjust-A-Vue tilt handle	Current-production body material (ABS vs. bakelite/phenolic) is [LIKELY], not confirmed by Simpson in these sources	Vol 2 §5
Roll-Top (“RT”)	Fitted carrying case with a sliding/rolling side-rail cover; fuses reached under a rotating silver plate	Applies old (an early original 260 was photographed in roll-top) and modern (260-7PRT, 8RT, 8PRT); ≈9 × 6½ × 4½ in, ~5½ lb	Vol 2 §5
Red vs black case	Current 260-8 product photos show a red option; classic vintage units are black bakelite	No series-discriminator rule found — red is a cosmetic/marketing option on modern units only. Do not caption current-production red/black as meaningful	Vol 2 §5
AFP-1 (military 5P)	Rubber feet screwed onto the corner bumps; FSN 6625-985-3951	U.S. military version of the 260-5P; powered by a D cell + an Eveready 417 15 V battery (AFP-1-specific — do NOT generalize this 15 V figure to any other series)	Vol 2 §5
Military cal bulletins	TB 9-6625-2352-35 (covers 260 up to Series 5); TB 9-6625-2354-35 (Series 6–8)	Confirms sustained military use; no confirmed “TS-###” JAN/AN type number exists for the 260 — don’t assert one	Vol 2 §5

⚠ Danger — Don’t repeat the “official US Navy standard” / “Bell System standard” claim as fact — only generic WWII-military field use is manufacturer-confirmed in the sourcing behind this dive. Detail: Vol 1, Vol 2 §1.

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6.9 Scale-Reading Quick Reference

Table 9 — 8. Scale-Reading Quick Reference

Scale feature	What it’s for	How to read it	Detail
Mirror band	Eliminates parallax (Series 4M on, standard from Series 8)	Move your eye until the needle hides its own reflection in the mirror strip — that’s the true reading angle	Vol 3 §8
Cascaded V/mA scales	One arc serves every DC volts/current range	Read the arc number, then apply the range multiplier mentally (e.g. reading “25” on the 0–250 arc with the switch on 250 V = 25 V is wrong — check which printed arc matches your range: the 260 face carries 0–10, 0–50, 0–250-style arcs, pick the one your switch position was derived from)	Vol 3 §8
Ohms scale	Reads resistance	Reversed and non-linear: zero Ω is at the right, infinity at the left; the scale compresses toward the high end — read carefully above center-scale	Vol 3 §6, §8
dB scale	Audio/line level relative to 1 mW into 600 Ω	Add the range’s dB offset (each AC voltage range has its own dB adjustment printed near the switch legend) to the scale reading	Vol 3 §7, §8
Mechanical zero	Pointer rest position	Set with no leads connected, via the screw-slot adjuster below the glass	Vol 4 §1
Ohms-zero	Corrects for battery age each ohms range	Short the leads, turn ZERO OHMS until the needle reads 0 Ω at the right-hand end — do this on EVERY ohms range, every time you switch ranges	Vol 4 §6, Vol 5 §4

Note — The instrument is calibrated horizontal. A reading taken with the meter propped vertically on its Adjust-A-Vue handle can drift slightly off the calibrated figure — fine for troubleshooting, not for a precision check. Detail: Vol 3 §1, Vol 5 §4.

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6.10 Measurement Recipes (Function Selection)

Table 10 — 9. Measurement Recipes (Function Selection)

Task	Function/range	Leads	Technique	Detail
Mechanical zero check	—	none connected	Screw-slot adjuster below the glass, set pointer to left-hand zero	Vol 4 §1
DC volts, unknown magnitude	DC volts, highest range first	red=+, black=COMMON−	Step down a range at a time; never guess low on an unknown source	Vol 4 §3
AC volts, line/audio	AC volts	either lead, non-polarized	Remember: average-responding, calibrated to RMS of a pure sine — a distorted waveform will read wrong	Vol 4 §4
DC current	mA/µA/10 A, break the circuit and insert in series	red=+, black=COMMON−	Start on the highest current range; step down	Vol 4 §5
Resistance / continuity	R×1, R×100, or R×10,000	either lead (internal battery)	Zero the leads first on every range (§10.3), then measure — circuit must be de-energized	Vol 4 §6
Diode test (both directions)	R×1 or R×100	probe both ways	Low reading one way (forward), very high/infinite the other (reverse) — a known-current, hands-on test a DMM diode-check function doesn’t replicate the same way	Vol 1, Vol 4 §6
Transistor junction test (B-E, B-C)	R×1 or R×100	probe base-to-emitter, base-to-collector, both directions	Same diode logic applied per junction; asymmetric readings both ways = healthy junction	Vol 1, Vol 4 §6
Capacitor “kick” check	R×10,000 (highest ohms)	probe across the cap	Needle kicks toward low-Ω then relaxes back toward infinity as the cap charges from the internal battery — a leaky cap fails to relax fully	Vol 1, Vol 4 §6
Output / dB (audio line, AC-coupled)	Output	across the line	AC component only; blocks up to 350 VDC — don’t rely on it for higher-voltage DC blocking	Vol 3 §7, Vol 4 §7
>1000 V DC/AC	5000 V jack + external HV probe	probe accessory required	Not a switch position — extends range only with the accessory in the “5000 V.” jack	Vol 3 §3, Vol 4 §8
Battery-health check	R×1/R×100 and R×10,000, leads shorted	—	If ZERO OHMS can’t reach 0 Ω, replace the corresponding battery (§10.3)	Vol 4 §6, Vol 5 §4

Note — Always select the highest applicable range first on an unknown voltage/current and step down — this protects the movement from an unexpected overload on non-P models, which lack the resettable relay. Detail: Vol 4 §2, §9.

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6.11 Refurb Quick Steps

6.11.1 Battery-holder clean & replace (the #1 260 refurb — Jeff’s actual 6P job)

1. Remove both batteries; inspect the D-cell spring clips and the 9 V polarized snap for white/green crust.
2. Neutralize alkaline salts — white vinegar on a Q-tip, or a baking-soda paste. Work it into the corrosion.
3. Rinse, then flush with isopropyl or denatured alcohol to displace water and dry fast.
4. Burnish the spring contacts lightly (fine abrasive or a fiberglass pen) until bright metal shows.
5. Finish with DeoxIT on the contacts to protect against re-corrosion.
6. If a clip is too far gone to save: fabricate/source a replacement spring-steel clip, or wire in a small AA/D holder to the original contact points as a practical substitute (no Simpson OEM clip part number is confirmed available). Re-test: can you zero R×1/R×100 and R×10,000? If yes, the holder repair worked.
7. Prevention (from the manual): pull batteries if the meter will sit unused >30 days.

Detail: Vol 5 §1 (full write-up + Jeff’s before/after case study).

6.11.2 Range-switch DeoxIT

1. Spray DeoxIT D5 (or a proper electronics contact cleaner) sparingly into the wafer switch — don’t flood it.
2. Cycle the switch through every position, many times, to wipe the wafer contacts against the cleaner.
3. Wipe off excess. Follow with a light DeoxIT film to protect the contact.
4. Symptom this fixes: intermittent, jumpy, or dead readings on some ranges; a noisy ohms-zero.

Detail: Vol 5 §2.

6.11.3 Ohms-zero = built-in battery test

Table 11 — 10.3 Ohms-zero = built-in battery test

Symptom	Diagnosis	Fix	Detail
Can’t zero R×1 or R×100	1.5 V D cell is weak/dead	Replace the D cell	Vol 4 §6, Vol 5 §4
Can’t zero R×10,000	9 V battery is weak/dead	Replace the 9 V (alkaline)	Vol 4 §6, Vol 5 §4
8P reset won’t hold, or trips spuriously	9 V weak (it also feeds the relay on P models)	Replace the 9 V first before suspecting the relay	Vol 2 §4, Vol 5 §7

Note — This is a free diagnostic every time you use the meter — zeroing ohms is a battery check. No separate battery-test procedure is needed. Detail: Vol 4 §6.

6.11.4 Other refurb touchpoints (quick index)

Table 12 — 10.4 Other refurb touchpoints (quick index)

Issue	Quick fix	Detail
AC ranges read low, DC/ohms fine	Aging copper-oxide (or old germanium) rectifier — replace with a matched germanium diode (1N87/1N270-class), watch polarity	Vol 5 §5, Vol 3 §5
Sluggish/dragging needle, pre-Series-6 unit	Pivot-and-jewel wear or a bent pointer — inspect under magnification; taut-band (Series 6+) is inherently more shock-tolerant	Vol 5 §3, Vol 2 §3
Meter reads slightly high across the board after decades	Alnico magnet aging — a factory/service-center recalibration corrects it via the trimmers (Series 4+ only; Series 1–3 have none)	Vol 5 §3, §4
Meter won’t read at all	Check F1 (1 A) and F2 (2 A) fuses first	Vol 5 §6, §12 below
8P won’t reset after a big overload	Reset button should pop up ≈3/16″ above the panel when tripped — press to reset; also verify with the R×10,000/−DC self-test (black lead to +1 V jack)	Vol 5 §7

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6.12 Failure Mode → Cause → Fix

The comprehensive table — §10 above is the procedure, this is the triage.

Table 13 — 11. Failure Mode → Cause → Fix

Symptom	Likely cause	Fix	Detail
Corroded/greenish battery compartment, dead or intermittent ohms	Leaked D-cell or 9 V dumped electrolyte onto the spring-clip contacts	Neutralize, rinse, alcohol-flush, burnish, DeoxIT (§10.1) — or replace the clip/holder	Vol 5 §1
Can’t zero R×1/R×100	Weak/dead 1.5 V D cell	Replace D cell (NEDA 13F)	Vol 5 §4
Can’t zero R×10,000	Weak/dead 9 V	Replace 9 V (NEDA 1604A alkaline)	Vol 5 §4
Intermittent/jumpy readings on some ranges only; noisy ohms-zero	Oxidized range-switch wafer contacts	DeoxIT + cycle the switch (§10.2)	Vol 5 §2
AC volts read progressively low over the years; DC and ohms unaffected	Aging copper-oxide (or old germanium) rectifier losing efficiency	Replace with matched germanium diode (1N87/1N270-class), watch polarity	Vol 5 §5, Vol 3 §5
Needle sluggish, sticky, or won’t return cleanly to zero (pre-Series-6 unit)	Pivot-and-jewel bearing wear or shock damage	Inspect under magnification; factory/service-center repair for bent pivots — taut-band (Series 6+) doesn’t share this failure mode	Vol 5 §3
Readings drift slightly high across the board after decades	Alnico magnet aging	Recalibrate via internal trimmers (Series 4+ only — Series 1–3 have none)	Vol 5 §3, §4
Meter dead on all ranges	Blown F1 (1 A) or F2 (2 A) fuse	Replace with exact part (§12 below)	Vol 5 §6
8P reset won’t hold / trips spuriously	Weak 9 V (also powers the relay) mimicking a relay fault	Replace the 9 V before suspecting the relay	Vol 5 §7, §10.3 above
8P continuity buzzer stuck or silent	Buzzer circuit is not protected by the electronic overload system — treat as a separate fault	Isolate and service independently of the relay/reset chain	Vol 2 §4
Broken meter glass	Physical damage	Do not operate — replace the glass before use	Vol 5 §3
Meter reads correctly but the case handle/feet are missing or non-original	Cosmetic/parts substitution over the unit’s life	Not a functional fault — note for provenance only, doesn’t affect ID confidence if the dial/jacks/switch tells agree	Vol 2 §6

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6.13 Fuse Part Numbers (Series 8 / 8P)

Table 14 — 12. Fuse Part Numbers (Series 8 / 8P)

Ref	Rating	Part	Interrupts	Location	Detail
F1	1 A / 250 V, 3AG, quick-blow	Littelfuse 312001 — replace with this exact type only	up to 250 V	Battery/fuse compartment, rotating cup — press then rotate	Vol 5 §6
F2	2 A / 600 V	Littelfuse Type BLS or Bussmann Type BBS	10,000 A interrupting capacity up to 600 V	Battery/fuse compartment	Vol 5 §6
—	0–10 A range	NOT FUSED — shunt wired straight to the ±10 A jacks	—	—	Vol 3 §4, §3 above

A spare 1 A fuse ships in the compartment on new units — check it’s still there before you need it. Detail: Vol 5 §6, §8.

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6.14 Parts Sourcing Quick Reference

Table 15 — 13. Parts Sourcing Quick Reference

Part	Source / part number	Notes	Detail
Manufacturer	Simpson Electric Company, Lac du Flambeau, WI — still in business, current production	(715) 588-3311; simpsonelectric.com	Vol 2 §7, Vol 5 §8
Test leads (Series 7/8/9)	Simpson Cat. No. 00043 — 48″, red+black, probe tip + screw-on alligator clips, 1000 V AC/DC / 10 A rated	Widely restocked (Newark, Mitchell Instrument, Techni-Tool)	Vol 5 §8
Test leads (Series 3–6)	Cat. No. 00125 (48″)		Vol 5 §8
Test leads (early 260)	Cat. No. 02055 (36″) with clip set 01927		Vol 5 §8
Low-ohms battery	NEDA 13F, 1.5 V D cell	Ordinary retail item	Vol 5 §8
High-ohms battery	NEDA 1604A, 9 V, alkaline (required on P models — powers the relay)	Ordinary retail item	Vol 5 §8
F1 fuse	Littelfuse 312001, 1 A/250 V 3AG		§12 above
F2 fuse	Littelfuse BLS or Bussmann BBS, 2 A/600 V		§12 above
5000 V HV probe	Extends DC/AC range via the “5000 V.” jack	Exact modern part number [UNCONFIRMED] — do not assert one (commonly cited “00033” not verified)	Vol 5 §8
260-8P Operator’s Manual	Simpson part 6-114339		Vol 5 §8
Replacement movements / NOS parts	Simpson service + collector/used market	No public part numbers confirmed	Vol 5 §8

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6.15 Safety DON’Ts

⚠ Danger —

• Never measure resistance on an energized circuit. The ohms ranges drive their own known current from an internal battery through a meter never designed to see external volts on that function — you risk the movement, the operator, and a wrong reading. De-energize and discharge first. Detail: Vol 4 §9.
• Never break the 10 A lead under load. The 0–10 A range is not fused — the shunt runs straight to the jacks. Disconnecting a lead carrying real current on this range risks an arc at the jack/plug. Detail: Vol 3 §4, Vol 4 §9.
• 1000 V AC/DC circuit-to-ground is the rated maximum (ANSI C39.5). Do not exceed it on any function, including with the meter floating. The 5000 V jack only extends range with the external HV probe — it does not raise the instrument’s own ground-referenced rating. Detail: Vol 1, Vol 4 §8–9.
• The Output jack blocks only to 350 VDC. Don’t rely on it as a general-purpose DC-blocking cap into a higher-voltage node. Detail: Vol 3 §7.
• Observe the one-hand rule above ~50 V and treat all “de-energized” gear as potentially hot until verified. See the shared safety doc _shared/legal_ethics.md. Detail: Vol 4 §9.
• Do not run with broken meter glass. Detail: Vol 5 §3.
• On P models, don’t ignore a tripped/won’t-hold reset — check the 9 V battery before suspecting the relay; a weak 9 V mimics a relay fault. Detail: §10.3 above, Vol 5 §7.

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6.16 Glossary (laminate-friendly)

Table 16 — Glossary (laminate-friendly)

Term	Meaning
D’Arsonval movement	The moving-coil galvanometer mechanism at the heart of every analog VOM — a coil in a fixed magnetic field, deflection proportional to current
Taut band	Suspension that replaces jeweled pivots with a tensioned metal ribbon — more shock-resistant, standard from Series 6
3AG	A standard glass fuse body size (¼″ × 1¼″) — F1 is a 3AG 1 A/250 V
NEDA	National Electrical Distributors Association — the battery-size/type numbering system (13F = D cell, 1604A = 9 V alkaline)
Adjust-A-Vue	Simpson’s trade name for the tilt-out carrying handle that props the meter up for viewing (introduced Series 2A)
AFP-1	The U.S. military-contract version of the 260-5P, FSN 6625-985-3951
FSN	Federal Stock Number — the pre-1974 U.S. military supply-catalog identifier (AFP-1’s is 6625-985-3951)
Ayrton shunt (ring shunt)	The resistor-ring topology used to derive multiple current ranges from one movement without disturbing calibration when switching ranges
Arc accuracy	Ohms-range accuracy expressed in degrees of scale arc rather than % of reading — a consequence of the non-linear ohms scale

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Sources

This volume synthesizes Vols 2–5 of this deep dive; it introduces no new claims of its own. The full per-claim sourcing, with confidence tags, lives in Vols 2–5. The primary documents behind the numbers on this sheet:

• Simpson 260 Series 8 Instruction Manual — Table 1-1 (full range set, accuracy), §1.2–1.3 (movement protection, batteries), §5 (maintenance)
• Simpson 260 Series 8P Instruction Manual — §1.2 (electronic overload protection), §1.3 (batteries), §1.4 (overload self-test), Table 1-2 (accessories, part numbers)
• simpson260.com per-model pages (Series 1 through 9S/9SP) — case, jack, movement, and dial-marking identification details
• radiomuseum.org per-model pages — independent production-date corroboration

See also B&K 375 VTVM and Simpson 311-2 VTVM for the high-impedance alternatives this cheatsheet doesn’t cover — reach for those on grid/screen/AVC nodes where the 260’s 20,000 Ω/V loading matters.